Skip to main content
PLOS One logoLink to PLOS One
. 2025 Dec 11;20(12):e0338497. doi: 10.1371/journal.pone.0338497

Predictors of early newborn deaths at Dar es Salaam public regional referral hospitals: A prospective observational hospital-based study

Grace Frank Mhando 1,2,3,#, Salvatory Florence Kalabamu 1, Maulidi Rashidi Fataki 1, Christina Clinton Galabawa 1,3,4, Kelvin Melkizedeck Leshabari 3,5,6,*,#
Editor: Chika Kingsley Onwuamah7
PMCID: PMC12698010  PMID: 41379804

Abstract

Introduction

Newborn deaths are still a concern to global health systems. Increased rates of documented hospital-based births are incongruent to newborn survival chances worldwide. Factors for that rather paradoxical observation are largely unknown. We aimed to assess predictors of early newborn deaths at representative metropolitan referral health facilities in Africa.

Materials & methods

We designed a prospective, analytical, hospital-based study in neonatal units at Dar es Salaam public regional referral hospitals, Tanzania. Neonates who died within the first 7 days of life were the target population. A pre-designed Case Report Form was the main tool for data collection. Multivariable binary logistic regression model was fitted to account for predictors of early newborn deaths after appropriate linear model validation. Proportion of early newborn deaths was the outcome variable.

Results

We recruited and analysed 2212 neonate-days of follow-up. Prevalence of early newborn deaths was 28.1%. Birth asphyxia (χ2 = 20.4, df = 1), preterm delivery (χ2 = 5.36, df = 1) and respiratory distress syndrome (χ2 = 30.94, df = 1) were associated with early neonatal outcomes. Predictors of early newborn deaths were neonatal respiratory rate (Tachypnoea – A.O.R.: 2.28 (95% CI.: 1.44–5.79); Bradypnoea – A.O.R.: 1.9 (95% C.I.: 1.02–12.3) and gestational age (Preterm delivery – A.O.R.: 1.48, 95% CI.: 1.11–2.09 and Post-term delivery – A.O.R.: 5.05, 95% C.I.: 4.49–32.0).

Conclusions

Early newborn deaths rate was relatively high in this study population. Newborns’ respiratory rates and gestational age at delivery were significant clinical factors associated with early newborn deaths in this study.

Introduction

Early newborn (neonatal) deaths remain a major public health concern worldwide, especially in Africa [1–3]. Early newborn deaths refer to mortal events happening within the first seven days of life, and late newborn deaths are those that happen after seven days but within the first 28 days of extra-uterine life [4,5]. At present, the demographic data on neonatal death risk factors tend to be controversial. For instance, the three commonest factors associated with early neonatal deaths in developed countries are prematurity, congenital abnormalities, and low APGAR scores [6]. In contrast, regions like Africa south of Saharan desert report the greatest rate of early neonatal deaths, mainly due to neonatal infections (e.g., sepsis, pneumonia), birth asphyxia as well as complications associated with preterm delivery [7]. Dar es Salaam city is among the fastest growing cities in Africa [8]. Dar es Salaam is scheduled to be the third most populous city in Africa by 2050 [8]. The interplay for the factors associated with early neonatal deaths in developing countries (Tanzania inclusive) tend to be multifactorial and non-specific. At the very least, little is known about the dynamics and interplay of those factors early in life.

There are several factors published in literature that are associated with early neonatal deaths in the health systems [1,9,10]. Conveniently, they can be summarized under neonatal, maternal and hospital system factors. However, in some reported statistics, these factors are either contradictory or antagonistic, dependent on a number of mechanisms. For instance, whereas early neonatal conditions/infections/deaths are justifiably attributable to maternal/obstetric factors, it is common knowledge that in most cases, late neonatal infections are attributable to neonatal/hospital-related factors. However, little is known about the changes brought by current epidemiological and demographic transition, especially in African countries.

At present, we acknowledge death statistics to be important for demographic studies, clinical as well as public health analyses. Vital system statistics are still in their infancy stage in Tanzania and Africa in general. They are generally deficient in terms of their significant under-registration of deaths, especially among <5-year population; extensive misreporting of age as well as significant ‘non-reporting’ of age-specific deaths, notably those that occur outside hospital premises. Amidst all the known challenges, there is still a glimmer of hope in utilization of hospital statistics, especially for early newborn deaths if prospectively collected.

In East African zone, Tanzania bears the greatest burden of neonatal deaths, accounting for 40% of all deaths in children under the age of five [11]. The most consequential aspect being 65.5% of all reported deaths occurred within first 24 hours of life [11]. Besides, there is palpable evidence that Dar es Salaam city is among cities with highest neonatal deaths in Tanzania [12]. However, the dynamics to which early neonatal deaths contributes to overall neonatal deaths statistics as well as causal pathways associated with the early deaths in that specific population cohort remains speculative [3]. We hypothesized the same mechanisms to be also applicable to other African countries but never fully explored before.

In Tanzania the crude early neonatal death rate is about 18 per 1000 live births [3]. The statistic is based on a national survey report of 2019 [3]. The published survey report also revealed significant variations in neonatal deaths across regions, with some regional variations also displaying inherent within-regional differences in mortality figures [3]. Recent study has shown that there is an increase of newborn deaths in urban areas such as Dar es Salaam compared to those delivered in rural areas [12]. However, factors that caused (are associated with) that rather paradoxical findings were not explored. Habitually, most of the retrievable peer reviewed publications in this specific agenda had either cross-sectional or retrospective designs [3,6,11]. We could not rely on those statistical estimates given inherent biases associated with their reported study designs. We therefore conceptualized this prospective analytical hospital-based clinical research to assess early neonatal mortality rate and associated factors at typical African urban regional referral hospitals.

Methods

Definition of key terms

Early neonatal period: The timespan between live-birth and 7 days post-delivery.

Early neonatal death/mortality: death events among live-newborns within 7 days of extra-uterine life.

Incident neonatal mortality rate: proportion of newborn deaths within the first 7 days of life

Study design and follow-up

We designed a prospective observational hospital-based clinical research study. Newborns were clinically followed-up immediately from birth up to (and including) day seven of extra-uterine life or death, which ever came first.

Study settings

The study was conducted at neonatal units of Amana, Mwananyamala and Temeke regional referral hospitals in Dar es Salaam. The named hospitals serve as the only highest points of referral hospitals for the public within the five administrative municipalities in Dar es Salaam metropolitan. Specifically, Amana is the top public regional referral hospital for Ilala municipality. Mwananyamala serves as the highest regional referral health facility for both Kinondoni and Ubungo municipalities. Temeke is reserved as the highest point of public referral centre for Temeke and Kigamboni municipalities. Thus, for all practical purposes, we considered those referral hospitals as being representative to Dar es Salaam mega city’s regional hospitals system.

Study population

Newborns admitted at regional referral hospitals in Dar es Salaam city.

Target population

All newborns who died within 7 days of life.

Sampling procedure

All newborns born at Amana, Mwananyamala and Temeke between 17 May and 16 November 2023 were eligible to be included into the study. A minimum sample of at least 319 newborns was enough to achieve study power of at least 80% within 5% level of significance. Initial plan was to employ a simple random sampling (without replacement) technique but since the study resources allowed inclusion of all neonates who met the inclusion criteria in the study timespan, all neonates who met the study’s inclusion (and without exclusion) criteria; and were delivered at the study settings during the study period were therefore recruited.

Recruitment and study duration

Newborns were recruited immediately after birth at the study sites. Recruitment was from 17th May 2023 to (and including) 16th November 2023. Incident mortality rate was the main outcome measure for this specific agenda. Specifically, neonates born (and admitted) at study sites within 7 days of life were recruited into the study. Moreover, mothers of newborns at the study settings who were referred to higher facilities (i.e., Muhimbili National Hospital) had newborns retained at the facilities as per existing guidelines at Dar es Salaam regional referral hospitals; and therefore their newborn babies were also eligible to be part of the study. Neonates who were beyond seven days of life were excluded from this study.

Data collection procedure

The pre-designed Case Report Form (CRF) was used for data collection. Specifically, it contained five different sections namely – demographics, maternal history in ante-partum and labour times, data during birth as well as immediate and underlying causes of deaths. An additional section on hospital-related data was also part of the CRF. The Case Report Form (CRF) was constructed by reflecting the study objectives and current good clinical practice guidelines. Before actual collection, the CRF was pilot-tested at two different private facilities for a duration of 5–7 days in order to assess measure of test-retest reliability as well as construct validity scores of tool items. Data collected also included verifications from RCH-cards, neonatal registration system (TEHAMA) as well as separate CRF-led interviews with mothers from each neonate admitted. Besides, each recruited neonate had physical examination performed by either the Principal Investigator (PI) or the research team members (MD-registrars at paediatrics depts. of Amana, Mwananyamala and Temeke hospitals). There was a 1-day research training for all research team members during pilot testing of the tool. Specifically, the training involved all research team members on aspects of good clinical and research ethics practice.

Variable design and measurements

Early (≤ 7 days) neonatal death/mortality was the main outcome variable while a series of neonatal (age – in days, gender, birth weight – in kg, temperature in Celsius scale, heart rate – in beats/min, respiratory rate – breaths/minute, heart murmur, neurological state, abdominal distension, enlarged organ, abdominal masses, Apgar scores [1st and 5th minutes] at birth, oxygen saturation at birth, random blood glucose (in mmol/L) at birth, time [approximated to nearest hours] to start breast feeding, presenting complaint(s) in the neonatal wards; maternal (date of birth of the mother, highest level of education, mother’s current occupation, religious affiliations, residence, marital status, mode of delivery, birth status [singleton or multiple gestation], preceding birth interval, number of antenatal visit during pregnancy, partographic findings, type of delivery [spontaneous vaginal delivery, Caesarean birth or instrumental delivery], history of maternal fever, meconium stained, premature rupture of membrane, chorioamniotis, antepartum haemorrhage) as well as hospital system factors [staff cadre level delivering the baby, time-to-entry into the neonatal ward] were set as independent variables.

Data processing and analysis plan

All data collected were double entered in a pre-designed template using Epi info statistical software version 7.4 (Epi-Info ™ CDC – Atlanta, USA). Data cleaning (e.g., checking for missing value, errors in data entry) was done on EPI INFO software version 7.4 and then exported to SPSS (IBM – Illinois, USA) version 23 for analysis. Since all continuous data displayed skewed distributions, they were summarized using median and inter-quartile range while categorical data were summarized using frequency and proportion. Besides, for selected categorical variables, their association with early neonatal mortality were assessed using likelihood ratio-based chi-square test with corresponding degrees of freedom. On death patterns, the International Classification of Disease number eleven ICD-11 were applied to label underlying causes of deaths. Incident early neonatal death/mortality rate was computed by direct method. Simply stated, we considered the ratio between number of newborn deaths occurring within 7 days of extra-uterine life to newborn-time pair of follow-up. Moreover, we also included analysis findings of prevalence mortality rate among study participants. To analyze predictors for early deaths, a multivariable binary logistic regression model was used to analyze predictors for early neonatal mortality after appropriate validation of linear model assumptions. Besides, a test for interactions (effect modifiers) was also done during multivariable binary logistic regression model fitting.

Ethical clearance and informed consent

Ethical clearance for the study was sought from the Institutional Research Committee of the Hubert Kairuki Memorial University in Dar es Salaam, Tanzania. Permission to conduct the study at the study sites was sought from Medical Officer in-charge of Amana, Mwananyamala and Temeke regional referral hospitals. Prior to recruitment of each neonate, mothers were approached for written informed consent that included brief summary of the study goals, risks and benefits of their newborns participations, voluntary nature of each baby participation (including the clause that inclusion/withdrawal to participate was free at any time without any compromise to available care at the facility), and that their babies were to be subjected to routine physical examination on enrollment.

Results

We successfully recruited and analysed a total of 2212 neonates-days of follow-up at Amana, Mwananyamala and Temeke regional referral hospitals in Dar es Salaam. We observed a slight male preponderance (n = 200, 54.1%) among followed-up newborns delivered at study sites. Moreover, majority (n = 263, 71.1%) were delivered by spontaneous vertex delivery, Caesarean delivered babies accounting for 28.4% (n = 105) and the rest (0.5%) being delivered by assisted deliveries. On maternal baseline clinical characteristics of studied newborns – more than half (50.8%) were multigravidae, 1.1% had obstructed labour, antepartum haemorrhage was rarely (0.3%) observed. On average, mothers of newborns attended a median of 4 (IQR: 3–5) antenatal care clinics. Moreover, on socio-demographic baseline characteristics included more than half (61.8%) had secondary education, 48.4% were self-employed while 43.2% were unemployed. Besides, we also found the prevalence of deaths among followed-up babies to be 28.1% at the study sites during the study period. Interestingly, more than half (52.8%) of the reported early neonatal deaths occurred within the first 24 hours after delivery. Table 1 below summarises the baseline characteristics of studied neonates:

Table 1. Selected baseline characteristics of newborns followed up at Amana, Mwananyamala & Temeke regional referral hospitals (May – November 2023).

Selected Neonatal Continuous Variables
Continuous variable Median* Inter-quartile range*
Newborn age (in completed days) 6 4 - 7
Apgar score at 1st minute 7 6–8
Apgar score at 5th minute 10 7–10
Birth weight (kg) 2.7 2.0–3.2
Gestational age at birth (weeks) 38 35–39
Oxygen saturation on admission (%) 90 87 - 95
Respiratory rate (breaths per minute) 60 49–68
Temperature - oC 36.8 36.6–37.8

Note: *Median and inter-quartile range were used as summary measure of central tendency for all continuous variables since they all had skewed distribution during initial data exploration.

In total, the incident unit of neonate-days of follow-up was derived by following up 370 newborns between May and November 2023. Besides, it was also of interest to assess association between neonatal diagnoses (on admission) and early neonatal death. The decision to select diagnoses reflected top 10 diagnoses reported in neonatal wards at Dar es Salaam hospitals. Table 2 below highlights the summary statistics:

Table 2. Selected neonatal diagnoses on admission associated with early neonatal outcomes.

Factors Alive Dead Chi-square** df p-value
Birth asphyxia
 Evident 75 56 20.4 1 0.000
 Non-evident 191 48
Prematurity
 Evident 82 46 5.36 1 0.02
 Non-evident 184 58
Early-onset neonatal sepsis
 Evident 110 32 3.108 1 0.078
 Non-evident 156 156
Respiratory distress (RDS)
 Evident 15 28 30.94 1 0.000
 Non-evident 251 76
Meconium aspiration
 Evident 17 13 2.97 1 0.085
 Non-evident 249 91

*NB: Total was greater than (N = 370) due to multiple diagnoses on admission. For instance, some neonates were admitted with both birth asphyxia and prematurity. ** Chi-square test statistics included Yates’ continuity corrections.

Since all the analysed variables above (Table 2) were categorical by design, the chi-square test (with corresponding degrees of freedom) adopted Likelihood Ratio Chi-square test statistics. Besides, the fact that observed statistics between variables had unequal frequencies, all Chi-square test scores were subjected to Yates’ continuity correction. Lastly, the main analysis included estimates of both crude and multivariable binary logistic regression for factors linearly associated with early newborn deaths at study settings. Prior to fitting a binary logistic regression model, we assessed the residuals of all maternal, neonatal and hospital related factors for normality, homoscedasticity, autocorrelation, significant multi-collinearity as well as linearity assumptions against the outcome variable. For all categorical variables had dummies made and the reference category/values as indicated.

Majority of the studied factors failed to meet the assumptions of linear model fitting in exception to maternal age and gestational age [in completed weeks] at delivery (maternal factors); respiratory rate, Apgar scores (at both 1st and 5th minutes), temperature, gender and birth weight (neonatal factors). For hospital system characteristics, we included cadre of the healthcare worker who delivered the baby, hospital name (coded as centre ID), number of qualified neonatologists, availability of neonatal ICU as well as presence/absence of visible emergency neonatal resuscitation protocol. In exception to hospital name (centre ID), all other hospital-related factors failed in one or more tests of linear model assumptions during validation of linear model fitting. They were thus discarded.

Table 3 below provides the statistical summaries of interest from the combined univariate and multivariable binary logistic regression outputs:

Table 3. Multivariable analysis of factors associated with early newborn deaths in Dar es Salaam public regional referral hospitals.

Crude/unadjusted Analysis Adjusted/ Multivariable analysis
Variable name Crude/unadjusted O.R. 95% C.I. P-value A.O.R. 95% C.I. P-value
Constant 0.071 0.04–0.09 0.000 0.066 0.04–0.341 0.000
MATERNAL FACTORS
Mode of delivery – svd 0.736 0.44–1.24 0.25 1.039 0.57–1.91 0.901
Mode of delivery – C/S 1 1
ANC visits (frequency) 0.882 0.72–0.93 0.003 0.882 0.75–1.03 0.118
Maternal age – < 18 y 1.313 0.67–2.47 0.445 1.74 0.88–2.92 0.07
Maternal age - > 35 y 1.22 0.61–2.67 0.598 1.08 0.75–3.29 0.838
Maternal age – 18–35 y 1 1
NEONATAL FACTORS
Tachypnea (≥ 60b/min) 3.17 1.91–5.2 0.000 2.28 1.44–5.79 0.02
Bradypnoea (<40b/min) 3.68 1.47–17.7 0.04 1.9 1.02–12.3 0.03
Eupnoea (40–59 b/min) 1 1
Temperature (oC) 0.65 0.44–0.76 0.001 0.57 0.23–1.89 0.296
1st minute Apgar score 0.804 0.72–0.90 0.000 0.889 0.56–1.37 0.593
5th minute Apgar score 0.837 0.76–0.92 0.000 0.916 0.63–1.32 0.641
Preterm gestation age at delivery (<37 weeks) 1.96 1.43–2.55 0.000 1.48 1.11–2.09 0.015
Post-term gestational age (≥ 42 weeks) 6.4 4.31–22.78 0.000 5.05 4.49–32.0 0.001
Term gestational age at delivery (37–41 weeks) 1 1
Birth weight (kg) 1.000 0.99–1.00 1.00 1.000 0.99–1.00 1.00
Gender – female 1.101 0.69–1.73 0.68 1.111 0.64–1.90 0.701
Gender – male 1 1
HOSPITAL FACTORS
Centre (Amana) 0.315 0.18–0.54 0.000 0.330 0.18–0.61 0.000
Centre (Mwananyamala) 2.971 1.23–7.19 0.016 `3.914 1.44–10.62 0.007
Centre (Temeke) 1 1

Note: Goodness of fit (Hosmer Lemeshow) χ2 test = 4.61 df = 4.

Discussion

Our analysis revealed almost a third of all sick admitted babies in the study settings died during follow-up period. This observed statistic is interesting for the following reasons. First, there appears to be missing targets in most interventions and strategic efforts to reduce newborn deaths at the study settings. Second, as per the final multivariable analysis, factors associated with early newborn deaths among Dar es Salaam hospitals were unlikely to be uniform. For instance, whereas babies delivered at Amana regional referral hospital were on average up to 60% less likely to die during the first seven days of life compared to those born at Temeke regional referral hospital, babies born at Mwananyamala regional referral hospital were observed to have the highest statistical risk of deaths of all the three studied hospitals. Since the three hospital facilities are all in the same service rank (regional referral hospitals), and at present public referral facilities, managed and owned by the central government, we do believe the observed statistical findings to be due to (an)-other hidden factor(s) that is/are rampant but never documented/studied before. We thus, wish to call for more analytical studies on this specific research agenda.

Our current statistics on early newborn deaths and the associated factors are not unique to Dar es Salaam/Tanzania environment. In fact, previous reports from other parts of Africa have yielded near the same findings. For instance, Weddith and his colleagues in Nouakchott, Mauritania reported a point prevalence of early newborn deaths of around 34.7% [13]. It was a cross-sectional study on factors associated with early neonatal mortality published back in 2019 [13]. The estimates from Mauritania, though alarming were for all practical purposes not significantly different from ours [13]. Other investigators who reported findings on risks of early neonatal mortality from referral hospitals included Tesfaye and collegues whose reported statistics was more than half (54.7%) of studied babies reportedly dying within the first seven days of life [14].

Clinical factors associated with early newborn deaths were also assessed in this study. On statistical grounds, respiratory rate and gestational age at birth were significantly observed to be associated with chances of early newborn deaths in our current linear model findings. Specifically, whereas tachypnoeic (faster than normal breathing) newborns had about 2.3 folds statistically significant increased risks of death up and above eupnoeic (normal breathing rate) newborns, those with bradypnoea (slower than normal breathing rates) had up to 2-folds statistically significant increased risks of death compared to eupnoeic newborns, all other factors in check. We have several alternative explanations for those findings. First, since the number of bradypnoeic children were relatively fewer, it is equally likely that bradypnoea was a spurious observation in view of the statistical artefacts due to smaller number of bradypnoeic (relative to tachypnoeic and eupnoeic) newborns. That is a design weakness that could not be corrected during analysis.

Otherwise, there are several reports that suggest tachypnea (and not bradypnoea) to be a more sensitive indicator of hypoxia among ill-neonates [15,16]. For instance, Rajesh and colleagues reported tachypnoea (breathing rate > 60 b/min) to be a more sensitive (sensitivity = 80%) indicator of hypoxia in critically ill newborns [15]. Thus, we could not rule out the possibility for the lag factor of bradypnoea in the risks of deaths in our cohort. Likewise, whereas preterm delivered newborns had up to 55% increased chances of death compared to term delivered newborns, those who were post-term deliveries had up to 5-folds increased risks of death compared to term delivered newborns.

Findings on clinical factors associated with early newborn deaths in this study are consistent with others reported (including in Tanzania) before [17–19]. For instance, Mangu and colleagues study on trends and patterns of newborn deaths in Tanzania revealed neonatal respiratory rate and distress to account for up to 20.8% of the causes for early newborn deaths [3]. Reyes and colleagues identified gestational age, respiratory rate, Apgar scores as significant risks associated with early neonatal deaths [18]. Moreover, whereas Reyes study findings were from outside Africa [18], Moshiro and colleagues [19] as well as Mangu and others [3] reported study findings were reported from Africa, in particular Tanzania.

Our current findings have several added advantages compared to others published before on the same topic. We conceived a prospective analytical study design and hence by design we could capture potential temporal association if present. Likewise, by virtue of our study design, both relative as well as absolute risks could be established since by default we could get population at-risk estimate. Most other scholars who reported similar findings had either cross-sectional [13,17] or retrospective observational designs [3,6,14]. Besides, the final analysis incorporated multivariable binary logistic regression model, and therefore potentially managed to account for common confounders during estimation of factors reported. However, there are a number of important limitations worth noted in this context. For instance, the entire study duration was limited by duration to six calendar months. There is palpable evidence in literature that shows mortality data in humans (neonates inclusive) to be affected by seasonality [20–23]. Thus, future studies on the same topic needs to account for the annual/seasonal variation of deaths among neonates, something that was beyond the current study power and design.

Besides, apart from the technical limitation in study duration coverage, the current study collected information from regional referral hospitals. Therefore, we could not completely rule-out potential referral biases in our findings. It is highly likely that the current estimate of early neonatal mortality to be an under-estimate of the true statistic, in lieu of the fact that we included only those newborns who were delivered at those facilities as well as considering the fact that normally referral bias results into negative biases, and hence likely under-estimation of the true statistic [24–26]. Moreover, it is important for readers and decision makers in mortality statistics to be aware of inherent limitations associated with our methods of analyzing current data. We relied on linear model analysis to derive our inferences. We thus wish to caution for and against possible overfitting and/or mortality risks perceptions.

The above two phenomena are common pitfalls in linear data analysis among both statisticians and demographers. To what extent do factors related to early neonatal deaths in real life obeying linear assumptions to be captured by our model is still thought provoking! However, on the basis of comparative crude and multivariable analysis done, our findings should be considered predictive enough on statistical grounds pending availability of better mechanistic model to explain better the interplay of those factors in real-world clinical scenario. Moreover, the fact that our linear model fitness was deemed statistically insignificant on Hosmer- Lemeshow Chi-square test, pinpointed to a probable linear model fitness. This gets an upper hand after realizing the fitted linear model had an intercept that was statistically significant associated with probable survival chances among studied babies. Thus, for all practical purposes, we do believe we managed to capture for factors associated with early neonatal mortality in the fitted linear model.

Otherwise, considering extensive global health efforts geared towards reduction of neonatal deaths, and especially early neonatal deaths throughout the world, and the marginal benefits vivid quantitatively, we have speculated possibilities of latent factors to be responsible for the last mile delivery effect against early neonatal survival chances. We have decided to speculate the ‘last mile delivery effect’ to be ‘latent factors’-equivalent and coin it as residual factors for early neonatal mortality. We do believe the hypothesized ‘residual factors for early neonatal mortality’ to have a potential for deleterious health consequences for newborns who managed to survive post-early neonatal era. We wish to treat that hypothesis as a potential research question worth future exploration. At present, there are mounting evidence that suggest transient and chronic ill-health in early childhood to be responsible to a myriad of negative health consequences throughout human lifespan [27–29]. We do hypothesise some of the ‘residual factors’ to be answerable for chronic childhood and adult diseases, rampant in present day Africa, including Tanzania [30–37]. However, most clinical research studies on mortality statistics across the entire human lifespan are hampered by lack of reliable and validated tools [38–43]. We have started joining hands locally for a pioneering move towards a global solution for not only delaying deaths in neonatal era but also establishing the pioneering move to account and prevent early life precursors of deaths [44].

Supporting information

S1 Data. Minimal dataset.

(XLS)

pone.0338497.s001.xls (209.5KB, xls)

Acknowledgments

We wish to convey our heartfelt gratitude to all newborn babies who participated in this study. Our sincere votes of thanks should also go to academic and administrative staff members of Hubert Kairuki Memorial University in Dar es Salaam, Tanzania. They provided a supportive academic environment that was necessary to make this study a success. Besides, special votes of thanks should go to staff at Amana, Mwananyamala and Temeke regional referral hospitals in Dar es Salaam, Tanzania. We also wish to convey our token of appreciation to Mr Faustine Mayunga, Drs Godfrey Swai and Mathew Mwanjali at Registered Trustees of Ultimate Family Healthcare in Dar es Salaam, Tanzania for their intellectual and moral support during data analysis and scientific writing workshops. Moreover, a sincere vote of thanks to the Coffeeshop Clinical Research & Scientific Writing joint-programme between Registered Trustees of Ultimate Family Healthcare and I-Katch Technology Ltd in Dar es Salaam. The knowledge and skills acquired during the scientific study designs, data analysis and even scientific writing courses will be forever memorable in our lives!

Data Availability

All relevant data are within the paper and its Supporting information files.

Funding Statement

The author(s) received no specific funding for this work.

References

  • 1.Lawn J, Cousens S, Zupan J, Bhutta Z, Darmstadt G, Martines J, et al. 4 Million neonatal deaths: When? Where? Why? Lancet 2005;365:891–900. [DOI] [PubMed] [Google Scholar]
  • 2.Costello A, Osrin D, Manandhar D. Reducing maternal and neonatal mortality in the poorest communities. BMJ. 2004;329(7475):1166–8. doi: 10.1136/bmj.329.7475.1166 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Mangu CD, Rumisha SF, Lyimo EP, Mremi IR, Massawe IS, Bwana VM, et al. Trends, patterns and cause-specific neonatal mortality in Tanzania: a hospital-based retrospective survey. Int Health. 2021;13(4):334–43. doi: 10.1093/inthealth/ihaa070 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.UNICEF. Neonatal mortality [Internet]. Child survival; 2023. [cited 2023 Jul 1]. Available from: https://data.unicef.org/topic/child-survival/neonatal-mortality/#:~:text=Achildborninsub,timesmorelikelytodie [Google Scholar]
  • 5.Sartorius V, Philibert M, Klungsoyr K, Klimont J, Szamotulska K, Drausnik Z, et al. Neonatal mortality disparities by gestational age in European countries. JAMA Netw Open. 2024;7(8):e2424226. doi: 10.1001/jamanetworkopen.2024.24226 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Roro EM, Tumtu MI, Gebre DS. Predictors, causes, and trends of neonatal mortality at Nekemte Referral Hospital, east Wollega Zone, western Ethiopia (2010-2014). Retrospective cohort study. PLoS One. 2019;14(10):e0221513. doi: 10.1371/journal.pone.0221513 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Lawn J, Zupan J, Begkoyian G, Knippenberg R. Newborn survival. In: Jamison D, Breman J, Measham A, et al., editors. Disease control priorities in developing countries. 2nd ed. Oxford University Press; 2006. [cited 2024 Oct 1]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK11775/ [Google Scholar]
  • 8.Leshabari K. Demographic transition in sub-Saharan Africa: from grassroots to ivory towers. In: Klimczuk A, editor. Demographic analysis: selected concepts, tools and application. London: InTech Open; 2021. [cited 2024 Nov 1]. Available from: https://www.intechopen.com/chapters/77806 [Google Scholar]
  • 9.Mohamed MA, Nada A, Aly H. Day-by-day postnatal survival in very low birth weight infants. Pediatrics. 2010;126(2):e360-6. doi: 10.1542/peds.2009-2810 [DOI] [PubMed] [Google Scholar]
  • 10.Bader D, Kugelman A, Boyko V, Levitzki O, Lerner-Geva L, Riskin A, et al. Risk factors and estimation tool for death among extremely premature infants: a national study. Pediatrics. 2010;125(4):696–703. doi: 10.1542/peds.2009-1607 [DOI] [PubMed] [Google Scholar]
  • 11.Manji KP. Situation analysis of newborn health in Tanzania: current situation, existing plans and strategic next steps for newborn health [Internet]. Dar es Salaam; 2009. [cited 2024 Oct 1]. Available from: http://countdown2030.org/documents/2012Report/Tanzania_SituationAnalysis_Newborn.pdf [Google Scholar]
  • 12.Norris M, Klabbers G, Pembe AB, Hanson C, Baker U, Aung K, et al. A growing disadvantage of being born in an urban area? Analysing urban-rural disparities in neonatal mortality in 21 African countries with a focus on Tanzania. BMJ Glob Health. 2022;7(1):e007544. doi: 10.1136/bmjgh-2021-007544 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Weddih A, Ahmed MLCB, Sidatt M, Abdelghader N, Abdelghader F, Ahmed A, et al. Prevalence and factors associated with neonatal mortality among neonates hospitalized at the National Hospital Nouakchott, Mauritania. Pan Afr Med J. 2019;34:152. doi: 10.11604/pamj.2019.34.152.14683 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Tesfay N, Tariku R, Zenebe A, Dejene Z, Woldeyohannes F. Cause and risk factors of early neonatal death in Ethiopia. PLoS One. 2022;17(9):e0275475. doi: 10.1371/journal.pone.0275475 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 15.Rajesh VT, Singhi S, Kataria S. Tachypnoea is a good predictor of hypoxia in acutely ill infants under 2 months. Arch Dis Child. 2000;82(1):46–9. doi: 10.1136/adc.82.1.46 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Koum K, Njinkui N, Enyama D, Tagne L, Penda C, Kuemo F. Respiratory distress and predictors of mortality among term newborns hospitalised at a reference hospital in Douala, Cameroon. Afr J Integr Health. 2019;9(1b):132–42. [Google Scholar]
  • 17.Dhahir A, Alalaf S. Maternal and neonatal characteristics that influence early neonatal deaths in a maternity teaching hospital. Zanco J Med Sci. 2022;26(2):96–107. doi: 10.15218/zjms.2022.011 [DOI] [Google Scholar]
  • 18.Lona Reyes JC, Pérez Ramírez RO, Llamas Ramos L, Gómez Ruiz LM, Benítez Vázquez EA, Rodríguez Patino V. Neonatal mortality and associated factors in newborn infants admitted to a Neonatal Care Unit. Arch Argent Pediatr. 2018;116(1):42–8. doi: 10.5546/aap.2018.eng.42 [DOI] [PubMed] [Google Scholar]
  • 19.Moshiro R, Perlman JM, Mdoe P, Kidanto H, Kvaløy JT, Ersdal HL. Potential causes of early death among admitted newborns in a rural Tanzanian hospital. PLoS One. 2019;14(10):e0222935. doi: 10.1371/journal.pone.0222935 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Doblhammer G, Vaupel JW. Lifespan depends on month of birth. Proc Natl Acad Sci U S A. 2001;98(5):2934–9. doi: 10.1073/pnas.041431898 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Koffi AK, Libite P-R, Moluh S, Wounang R, Kalter HD. Social autopsy study identifies determinants of neonatal mortality in Doume, Nguelemendouka and Abong-Mbang health districts, Eastern Region of Cameroon. J Glob Health. 2015;5(1):010413. doi: 10.7189/jogh.05.010413 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Lowell WE, Davis GE Jr. The light of life: evidence that the sun modulates human lifespan. Med Hypotheses. 2008;70(3):501–7. doi: 10.1016/j.mehy.2007.05.053 [DOI] [PubMed] [Google Scholar]
  • 23.Nyári TA, McNally R. Seasonal variation in childhood mortality. J Matern Fetal Neonatal Med. 2020;33(24):4055–61. doi: 10.1080/14767058.2019.1594765 [DOI] [PubMed] [Google Scholar]
  • 24.Al-Hasan MN, Eckel-Passow JE, Baddour LM. Influence of referral bias on the clinical characteristics of patients with Gram-negative bloodstream infection. Epidemiol Infect. 2011;139(11):1750–6. doi: 10.1017/S095026881100001X [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Agniel D, Kohane IS, Weber GM. Biases in electronic health record data due to processes within the healthcare system: retrospective observational study. BMJ. 2018;361:k1479. doi: 10.1136/bmj.k1479 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Kokmen E, Ozsarfati Y, Beard CM, O’Brien PC, Rocca WA. Impact of referral bias on clinical and epidemiological studies of Alzheimer’s disease. J Clin Epidemiol. 1996;49(1):79–83. doi: 10.1016/0895-4356(95)00031-3 [DOI] [PubMed] [Google Scholar]
  • 27.Barker DJ, Winter PD, Osmond C, Margetts B, Simmonds SJ. Weight in infancy and death from ischaemic heart disease. Lancet. 1989;2(8663):577–80. doi: 10.1016/s0140-6736(89)90710-1 [DOI] [PubMed] [Google Scholar]
  • 28.Dover GJ. The Barker hypothesis: how pediatricans will diagnose and prevent common adult-onset diseases. Trans Am Clin Climatol Assoc. 2009;120:199–207. [PMC free article] [PubMed] [Google Scholar]
  • 29.Vaiserman AM, Collinson AC, Koshel NM, Belaja II, Voitenko VP. Seasonal programming of adult longevity in Ukraine. Int J Biometeorol. 2002;47(1):49–52. doi: 10.1007/s00484-002-0144-0 [DOI] [PubMed] [Google Scholar]
  • 30.Leshabari K, Ramji R. The pattern of infections among under-fives: a call for actions. DES Med Stu Jrnl. 2010;15(1):24–8. doi: 10.4314/dmsj.v15i1.49597 [DOI] [Google Scholar]
  • 31.Salum SS, Kalabamu FS, Fataki MR, Omary SA, Mohammed UH, Kizwi HA, et al. Asymptomatic hypoglycemia among preterm newborns: A cross-sectional analysis. PLoS One. 2024;19(4):e0301803. doi: 10.1371/journal.pone.0301803 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 32.Leshabari K, Ndonde W, Mbega S, Mbululo L. Predictors of cardiometabolic risks among typical African elderly population: analysis from Dar es Salaam, Tanzania. Diabetes Technol Ther. 2020;22:A214. [Google Scholar]
  • 33.Omary SA, Kalabamu FS, Fataki MR, Salum SS, Mohamed UH, Kimaro JG, et al. Severity and morphological characteristics of anaemia among 6 to 59 months old children in Temeke, Dar es Salaam-Tanzania: clinics based cross sectional analysis. East Afr Health Res J. 2024;8(2):188–94. doi: 10.24248/eahrj.v8i2.780 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Leshabari K, Chale G, Salim R. Ageing and HIV risk in non-gravid female humans. In: Shah Y, editor. RNA viruses infection. London: Intech Open; 2021. [cited 2024 Nov 2]. Available from: https://www.intechopen.com/chapters/80935 [Google Scholar]
  • 35.Chale GJ, Salim RM, Leshabari KM. Clinical indications for total abdominal hysterectomy among women seen in Dar es Salaam regional referral hospitals, Tanzania: a prospective, observational hospital-based study. Pan Afr Med J. 2021;38:10. doi: 10.11604/pamj.2021.38.10.17695 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Leshabari K, Magoma R, Mtitu I, Mwanjali M, Swai G, Mrina M. Prevalence of Mild Cognitive Impairment (MCI) and probable dementia in a selected cohort of senior citizens residents of Dar es Salaam, Tanzania. Eur Geriatr Med J. 2023;14(suppl.1):S12. [Google Scholar]
  • 37.Leshabari KM, Biswas AK, Gebuis E, Leshabari SC, Ohnishi M. Challenges in morbidity and mortality statistics of the elderly population in Tanzania: a call to action. Qual Ageing Older Adults. 2017;18(3):171–4. doi: 10.1108/qaoa-09-2016-0035 [DOI] [Google Scholar]
  • 38.Manzotti A, Cerritelli F, Lombardi E, La Rocca S, Biasi P, Chiera M, et al. The neonatal assessment manual scorE: a reliability study on hospitalized neonates. Front Pediatr. 2021;9:715091. doi: 10.3389/fped.2021.715091 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Kovacs D, Msanga DR, Mshana SE, Bilal M, Oravcova K, Matthews L. Developing practical clinical tools for predicting neonatal mortality at a neonatal intensive care unit in Tanzania. BMC Pediatr. 2021;21(1):537. doi: 10.1186/s12887-021-03012-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Leshabari K. Reliability and validity of clinicopathological features associated with frailty syndrome in elderly population. In: Palermo S, editor. Frailty in the elderly – understanding and managing complexity. IntechOpen; 2021. [cited 2025 Sept 1]. Available from: https://www.intechopen.com/chapters/73143 [Google Scholar]
  • 41.Palermo S. Frailty in the elderly – understanding and managing complexity. London: IntechOpen; 2021. [cited 2025 Sept 1]. Available from: https://www.intechopen.com/chapters/73143 [Google Scholar]
  • 42.Leshabari K, Magoma R, Mtitu I, Mwanjali M, Swai G, Mrina M. Diagnostic performance of a proposed Dar es Salaam Dementia Screening Test. Eur Geriatr Med. 2023;14(suppl. 1):S122. [Google Scholar]
  • 43.Leshabari K, Msaki A, Bigambo J, Sindato M, Mrina M, Mwanjali M, et al. Validation of the Dar es Salaam Dementia Questionnaire (Dar-DEMEX) in a community residents of seniors in Dar es Salaam, Tanzania. Eur Geriatr Med J. 2024. [cited 2025 Sept 1]. Available from: doi: 10.1007/s41999-024-01090-y [DOI] [Google Scholar]
  • 44.Swai G, Leshabari K. The new paradigm of local research and innovations by local health professionals. Tanz J Health Res. 2022;23. [Google Scholar]

Decision Letter 0

Chika Onwuamah

16 Mar 2025

Dear Dr. Leshabari,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Apr 30 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Chika Kingsley Onwuamah, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf

2. We note that your Data Availability Statement is currently as follows: All relevant data are within the manuscript and its Supporting Information files.

Please confirm at this time whether or not your submission contains all raw data required to replicate the results of your study. Authors must share the “minimal data set” for their submission. PLOS defines the minimal data set to consist of the data required to replicate all study findings reported in the article, as well as related metadata and methods (https://journals.plos.org/plosone/s/data-availability#loc-minimal-data-set-definition).

For example, authors should submit the following data:

- The values behind the means, standard deviations and other measures reported;

- The values used to build graphs;

- The points extracted from images for analysis.

Authors do not need to submit their entire data set if only a portion of the data was used in the reported study.

If your submission does not contain these data, please either upload them as Supporting Information files or deposit them to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. For a list of recommended repositories, please see https://journals.plos.org/plosone/s/recommended-repositories.

If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially sensitive information, data are owned by a third-party organization, etc.) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent. If data are owned by a third party, please indicate how others may request data access.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

Reviewer #1: Partly

Reviewer #2: Partly

Reviewer #3: Yes

Reviewer #4: No

**********

2. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: No

Reviewer #2: No

Reviewer #3: Yes

Reviewer #4: No

**********

3. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

Reviewer #1: Thank you for the opportunity to review the manuscript “Predictors of Early Neonatal Mortality at Public Regional Referral Hospital in Dar es Salam Tanzania: A prospective observational hospital-based study.

General Overview: The proposal addresses important issues concerning child health in the public health space, specifically neonatal mortality and its associated predictors.

The Outline of the manuscript is in tandem with the journal.

Abstract:

Methods. The target population should be rephrased as all neonates in the hospital. The outcome is the death of neonates within 72 hours of life.

The phrase “Unless otherwise specified, an α-level of 5% was used as a limit of type 1 error rate in findings” should be deleted from the material and methods in the abstract as it is a hanging tense”.

Conclusion: The word relatively should be deleted from the sentence.

Introduction:

Well written, with the need to avoid some informal words in between tenses.

Rewrite/delete the tense, for instance, as: The three commonest factors associated with early neonatal mortality are…

Paragraph 2, line 3: Delete the word “Antagonistic”. Please kindly explain the sentence, “However, in some reported statistics, these factors are either contradictory or antagonistic, dependent on a number of mechanisms”

Methods:

What is the difference between the study population and the targeted population? I guess the target population is the author's choice when defining the study’s primary outcome.

The authors also need to clarify the participants enrolled. Were the participants only those delivered in the three referral hospitals, or did they include those referred from other hospitals for continued care in the three centres? This is important because there seems to be some conflicting tense of eligibility in the sample procedure sub-section and the recruitment and study duration sub-section.

The last sentence in the data collection procedure section appears redundant advise to delete it.

Variable Design and Measurement: If children delivered out of the referral facilities were involved in the study. Then, the place of delivery should be included as a variable.

Ethical clearance: Please do rephrase the tense: “that their babies will be subjected to minimal physical discomforts, especially during physical examinations as well as where to send their queries (if any) regarding the study/investigations in general” to the babies will be subjected to routine physical examination on enrollment

What is the formula for computing the Early Neonatal mortality rate

Results:

The results section is poorly written. It is just only a display of tables without phrases or tenses to describe the resulting output. The authors need to redo the result section significantly.

Example: Tabe 1:

The median age of participants enrolled in the study was 6 days, with a male-to-female ratio of (1:0.8). 71% of the participants were delivered via SVD, 26% via cesarean section

In table 1: Were the assisted delivery through SVD or C/S

Can the Place of delivery be better categorised? I presume all the hospital deliveries were delivered in the three primary referral facilities in the study, while the health centre, dispensary, home and others were out of the facilities. What does the other imply since it is only one subject?

Table 2: This table is confusing. The authors should help depict more clearly. The need for clear definitions of terms or diagnoses is important.

Where all the RDS associated with Prematurity or the MAS associated with Birth Aspyxia

Discussion:

Poorly written discussion.

The first paragraph appears more as postulations rather than the true summary of the findings from the results.

The assertion of residual factors seems unclear. What does the author mean by the term residual factors?

Reviewer #2: The manuscript needs major revisions in all the sections, especially the methods, result and discussion areas. These have been highlighted in the review report. A definition of terms used should be included to aid understanding of the subject.

Reviewer #3: The authors are invited to address the section on “Data collection procedure” as follow:

1.Data quality issues need attention. Clinical and laboratory data were collected on neonates from three hospitals hence three different research teams thus raising data quality assurance concerns. It is commendable that the instrument used to collect data was pilot-tested. However, there was no indication that the investigators were trained to use the tool. What did the authors do to address data consistency was assured? The study collected laboratory as well as clinical data. Did the Pediatric MDs (residents) attend all the deliveries and conducted the Apgar scoring or the midwives? Did all hospitals use the same (type, model) weighing scales and pulse oximeters for the babies? Did the authors use one lab or each hospital conducted their laboratory analysis (eg blood glucose)? Quality control measures for the clinical measurements and labs should be reflected in the write up.

2.Respiratory rate was one of the clinical parameters that predicted mortality as reported in this communication. In what way did the respiratory rate contribute to mortality? One would have expected that the pathological conditions that have bearing on the respiratory rate should have been factored into the analysis. Could this be reviewed and addressed?

Reviewer #4: The title sounds good with the intention of guiding Paediatricians and medical officers on the predictors of Neonatal mortality and ways to prevent such outcomes. However, the authors did not derive their conclusions from the study but a lot of assumptions. The authors are expected to respond to the following queries

1.What were the inclusion and Exclusion criteria

2 Three centres were chosen and the number of new born mortalities cannot be same therefore proportionate numbers should have been highlighted.

3. Were the children with congenital malformations included or excluded from the study

4. In the study " was premature rupture or prolonged rupture of membranes or both documented.

5.Results were not clear with too many jumbled information

6.How many babies actually died within the period was not stated except its readers teased out the number from table 1(370).Of these 370, from the table only 4 had their mothers less than 18 yrs and 35 > 35years. what about the others.

7.Are the causes of deaths of the same from all the centres

8. No table showed the predictors of neonatal mortality which is the title of this manuscript. Table 2 showed only the diagnosis and outcome but not predictors, neither did table 3. Some of the variables shown in table 3 were wt, sex , temp etc. What are the effects of these variables on neonatal mortality in terms of weight difference -prematurity,Large for age or small for age. How many female or males babies died, or what effect does hypothermia or hyperthermia or maternal age have on neonatal mortality.

8.Discussion was not based on the findings from the study eg such statement among others identified " its appears majority of the reported deaths occur during the first 24 hrs" . No evidence to suggest that from the results. Hence the discussion is not in line with study outcome or findings.

9.The use of the word "residual factors'. what are these residual factors. Did the study prove it. The authors will have to be cautious with use of such words in the manuscript.

The topic sounds good but the authors have not proven or highlighted the predictors of mortality in newborn babies in Tanzania such that a doctor practising in that part of the world would watch out for such predictors that can lead to mortality

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: Yes:  Abideen Salako

Reviewer #2: No

Reviewer #3: No

Reviewer #4: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachment

Submitted filename: Reviewers Comment PONE-D-25-05428.docx

pone.0338497.s002.docx (15.5KB, docx)
Attachment

Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Rev.docx

pone.0338497.s003.docx (17KB, docx)
Attachment

Submitted filename: PONE MS Reviewer recommendation.docx

pone.0338497.s004.docx (15KB, docx)
PLoS One. 2025 Dec 11;20(12):e0338497. doi: 10.1371/journal.pone.0338497.r002

Author response to Decision Letter 1


29 Apr 2025

REVIEWERS’ QUERIES/RECOMMENDATIONS SECTION

[PAGE NUMBER] AUTHORS’ RESPONSE CHANGES MADE

[YES/NO]

1. Abstract - Methods. The target population should be rephrased as all neonates in the hospital

Abstract

[pp. 2 ]

Indeed, in this clinical research, ‘target population’ was neonates who died within the first 72-hours of delivery.

All neonates in the hospitals were the study population and not the target population.

No

2. The phrase “Unless otherwise specified, an α-level of 5% was used as a limit of type 1 error rate in findings” should be deleted from the material and methods in the abstract as it is a hanging tense”.

Abstract

[pp. 2]

Deleted completely as suggested by the reviewers.

Yes

3. Conclusion: The word relatively should be deleted from the sentence

Abstract

[pp. 2]

Deleted completely as recommended by the reviewers

Yes

REVIEWERS’ QUERIES/RECOMMENDATIONS SECTION

[PAGE NUMBER] AUTHORS’ RESPONSE CHANGES MADE

[YES/NO]

4. The WHO definition of early neonatal death is death occurring in the first 7 days of life, not the first 3 days

Introduction

[pp.3] In this research paper, we adopted the American Academy of Pediatrics definition of ‘early neonatal death’ that refers to death occurring in the first 72-hours (3-days) of life.

We have also included ‘definition of terms’ in the manuscript

Yes

5. The “demographic data on neonatal death risk factors” are said to be “controversial”, but neither the factors nor the controversy are stated/explained

Introduction

[pp. 3]

We provided/stated the controversies associated with the term ‘early neonatal deaths’ in the introduction section.

Specifically, we highlighted the differences in the definition of ‘early neonatal death’ as to what appears to be informally referring to ‘American vs European’ standards. We specified that there appears to be confusion in literature as whereas American Academy of Pediatrics considers ‘early neonatal period’ to be within the first 72-hours after delivery, in Europe (including WHO) definition, the same observation refers to the first seven days of life

Yes

1. What is the difference between the study population and the targeted population? I guess the target population is the author's choice when defining the study’s primary outcome

Methods

[pp. 5]

Target population is defined in a standard format as population to which the primary research findings/outcomes will be applicable.

No

2. The authors also need to clarify the participants enrolled. Were the participants only those delivered in the three referral hospitals, or did they include those referred from other hospitals for continued care in the three centres? This is important because there seems to be some conflicting tense of eligibility in the sample procedure sub-section and the recruitment and study duration sub-section.

Methods

[pp. 5]

We only included newborns delivered at the study sites during this study period only. It was not clear where was the source of confusion to readers in the initial draft

Specifically, it is vividly written as

Sampling procedure: All newborns born at Amana, Mwananyamala and Temeke between 17 May and 16 November 2023 were eligible to be included into the study.

Recruitment and study duration: Newborns were recruited immediately after birth at the study sites. Recruitment was from 17th May 2023 to (and including) 16th November 2023.

No

1. The last sentence in the data collection procedure section appears redundant advise to delete it.

Methods

[pp. 6]

Deleted as recommended by reviewers

Yes

2. Variable Design and Measurement: If children delivered out of the referral facilities were involved in the study. Then, the place of delivery should be included as a variable.

Methods

[pp. 6]

We only included children born at the study sites in this study.

No

3. What data did those children admitted after 3 days of life contribute to the study outcome?

Methods

[pp. 5]

They will contribute in subsequent analysis (secondary data analysis) that will be published in the near future.

Yes

4. Data quality issues need attention. Clinical and laboratory data were collected on neonates from three hospitals hence three different research teams thus raising data quality assurance concerns.

It is commendable that the instrument used to collect data was pilot-tested. However, there was no indication that the investigators were trained to use the tool.

Methods

[pp. 6] Data quality assurance concerns were kept at near zero possibilities since

1.The tool was pilot tested

2.Research team members underwent a formal 1-day ‘good clinical and ethics research practice’ workshops done during the time of tools’ pilot testing.

3.Since all the three regional referral hospitals are financed by the same donor sources, they normally have the same lab and imaging tools. We also conducted a quick test-retest reliability as well as content validity analyses of all test results with no resultant statistically significant differences in findings during pilot test.

No

1. Very importantly, there was no definition of terms used in the paper. The definition/explanation of terms would have greatly facilitated understanding of the work

Methods

[pp. 5]

We have included a sub-section on ‘definition of terms’ in the methods section. For ease legibility, we decided to include it as the second sub-section, immediately after the study design section.

Yes

2. Ethical clearance: Please do rephrase the tense: “that their babies will be subjected to minimal physical discomforts, especially during physical examinations as well as where to send their queries (if any) regarding the study/investigations in general” to the babies will be subjected to routine physical examination on enrollment

What is the formula for computing the Early Neonatal mortality rate

Methods

[pp. 7]

We have made the changes as per the recommendations by reviewers

We have also included the definition and formula for computing early neonatal mortality rate used in this analysis.

Yes.

3. The number of babies recruited was not explicitly stated, and follow up days are not a part of recruitment

Results

[pp. 8] Number of babies recruited were explicitly stated in the manuscript using newborn-time of follow-up since the study was prospective by design. In classical epidemiology, studies adopting prospective design report total recruitment using person-time of follow-up rather than an absolute number characteristic in cross-sectional studies.

No

4. The results section is poorly written. It is just only a display of tables without phrases or tenses to describe the resulting output. The authors need to redo the result section significantly.

Results

[pp. 8-10] Results section has been extensively re-written as depicted in the new submitted manuscript file

Yes

1. It is also stated that the 3 main factors associated with early neonatal deaths, viz, neonatal, maternal and hospital system factors can be either contradictory or antagonistic without any explanation/examples of the contradictions/antagonism

Introduction

[pp. 3]

We have provided summary of the justifications behind both contradiction and antagonism.

Contradiction: the discrepancy in the definition of early neonatal period (death) between what appears to be ‘American vs European’ definitions.

Antagonism: differences in the causes of ‘early neonatal deaths’ between advanced economies vs. ‘low and middle income countries’

Yes

2. Babies were said to have been followed up for seven days or till death, whichever came first. Since the outcome of interest was mortality in the first 3 days, what was the significance of follow up beyond the first 3 days of life?

Methods

[pp. 5]

Investigators designed a research protocol on analyses for both deaths at day 3 and day 7 of life by design since even though the primary research question relied on ‘incident neonatal mortality and associated factors at day 3’ but there was a secondary research question that focused on analyzing ‘incident neonatal mortality on day 7’.

The original research paper will be on ‘early neonatal mortality and associated factors within 3 days of life’ and later on there will be another publication (secondary analysis!) for ‘incident neonatal mortality within 7 days of life’

No

Attachment

Submitted filename: RESPONSE TO REVIEWERS.doc

pone.0338497.s007.doc (74KB, doc)

Decision Letter 1

Chika Onwuamah

29 May 2025

Dear Dr. Leshabari,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Jul 13 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Chika Kingsley Onwuamah, Ph.D.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

Reviewer #3: All comments have been addressed

Reviewer #4: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #1: Yes

Reviewer #2: Partly

Reviewer #3: Yes

Reviewer #4: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #1: Yes

Reviewer #2: No

Reviewer #3: Yes

Reviewer #4: No

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: No

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

Reviewer #4: Yes

**********

Reviewer #1: The authors has provided needed answers and made correction to the intial review. The manuscript read better now

Reviewer #2: Although the issues raised in the previous review were responded to, a lot of the responses are inaccurate and highlight the need for the authors to endeavour to understand the subject matter of the research better. The detailed explanation is in the attached review report.

Reviewer #3: The data issue raised by me has been adequately addressed, thanks.

Reviewer #4: It is good to note that the authors have responded to some of the queries highlighted in the previous review. However, there are some unanswered questions to ensure this article reflects the topic which is Predictors of Neonatal deaths in 3 hospitals in Da res Salam .

1. Neonatal death mortality were used in several sections of the write up. The authors either sticks to Neonatal deaths or mortality and not death mortality

2. Some statements require references eg."Besides,

there is palpable evidence that Dar es Salaam city is among cities with highest neonatal deaths

in Tanzania"

3. The author would need to clarify some statements eg."Specifically,

neonates born (and admitted) at study sites within 37 days of life were recruited into the study."

I thought is about predictors of neonatal deaths occurring within 72 hrs of life

4. The authors did not discuss the possible hospital system factors that may be responsible for neonatal deaths which may serve as predictors or are these part of the residual factors.

5. The authors should highlight the possible residual factors responsible for neonatal deaths even if the study does not capture or what comprises the residual factors

6The predictors of death from this study were Birth Asphyxia, Prematurity and RDS. The authors did not extensively discuss their findings and reasons for the observations.

7 Does sepsis play any role in the mortality , the data did not display these findings apart from temp. recordings. What were the other risk factors for sepsis which could have worsened the mortality observed. These risk factors were mentioned as variables to be captured but were not analysed in the result section.

8 Table 2.. Factors should be changed to diagnoses. What was the total number of deaths even though they could have had multiple diagnosis.

8. Table 3 is deficient with information on the predictors, needs improvement. Maternal and Neonatal factors responsible or as predictors are not exhaustive

9. Authors should discuss their findings and give reasons or proffer reasons why the observations and relate it with other studies. Reviews in the discussions limited.

10 "Otherwise, we do believe the hypothesized ‘residual factors for early neonatal mortality’ to have a

potential for deleterious health consequences for newborns who managed to survive post-early"" What are these residual factors. The readers would like to know what makes up the residual factors and learn from it so as to provide better care for our babies.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #1: Yes:  Abideen Salako

Reviewer #2: Yes:  Agatha N. David

Reviewer #3: No

Reviewer #4: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachment

Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Rev.docx

pone.0338497.s006.docx (15.1KB, docx)
PLoS One. 2025 Dec 11;20(12):e0338497. doi: 10.1371/journal.pone.0338497.r004

Author response to Decision Letter 2


15 Aug 2025

Neonatal death mortality were used in several sections of the write up. The authors either sticks to Neonatal deaths or mortality and not death mortality.

Title – [pp. 1]

Abstract – [pp. 2]

Introduction – [pp. 3-4]

Methods – [pp. 5-7]

Results – [pp. 8-10]

Discussion – [pp. 11-13]

-Authors wholeheartedly agreed to use the word ‘deaths’ instead of mortality for wider legibility of the intended message.

YES

Early neonatal death is defined by the American Academy of Paediatrics (AAP) as death in the first 72 hours of life

This is incorrect; the AAP defines early neonatal death as death in the first 7 days of life, in line with the WHO (Paediatrics 2016. 137(5): e20160551). This was reaffirmed in December 2024.

Introduction - [pp. 3]

Methods – [pp. 5]

Authors accepted the standard definition as per the reviewers’ suggestion and hence had to change not only the definition of the term but also re-run the analyses that incorporated the former definition (early mortality ≤ 3 days – 72 hours) to a newer one of 7-days duration

YES

Some statements require references eg. "Besides, there is palpable evidence that Dar es Salaam city is among cities with highest neonatal deaths

in Tanzania”.

Introduction – [pp. 3]

Missing reference that had to be added

YES

The controversies are said to stem from the inconsistency between American and European/WHO definitions.

This is debunked by the congruity of the two definitions as shown above. I believe they were misled by the disparities discussed in one of their referenced articles (Ref. 5), which disparities in neonatal mortality rate (NMR) across several European countries, comparing mortality rates and gestational-age associated mortality between the countries with the lowest NMR and the other countries. This should be understood in context and has nothing to do with the stated objective of this study.

In addition, the antagonism/contradiction among maternal, neonatal and health system factors in NMR is yet to be explained. These unexplored health system factors may actually be responsible for the so-called residual factors that they believe contributed to the high mortality rate.

Introduction – [pp. 3]

The entire sentences have been deleted after changing the definition of early neonatal period from 3 days (72-hours) to 7 days post-delivery.

YES

The author would need to clarify some statements eg."Specifically,

neonates born (and admitted) at study sites within 37 days of life were recruited into the study."

I thought is about predictors of neonatal deaths occurring within 72 hrs of life

Methods – [pp. 5]

Authors changed the definition of early neonatal deaths from 3 days (72-hours) to 7 days.

YES

Follow up days beyond 3 days of life is said to be for another publication.

It should have been clearly stated that what was being reported in this manuscript is the 3-day NMR of a cohort of newborns followed up from birth to 7 days of life.

An answer to the previous reviews queries

Authors changed the definition of the concept ‘early neonatal period’/’early neonatal death’ from earlier 72-hours (3-days) to the current 7-days duration. The changes di not only affected the definition of terms but also changed even the analyses made by incorporating newborns up to 7 days.

YES

they said they only recruited babies born in the study hospitals.

This is refuted by this statement in the methods section: “Besides, we also recruited neonates who were referred/transferred from other lower hospitals to the study settings provided that they were ≤ 3 days old.”

Methods – [pp. 5]

Authors deleted that sentence and hereby declare that to have been an erroneous statement that was earlier refuted during protocol design. The error was introduced by one reviewer from IRB who directed investigators for those babies to be also included.

However, investigators rejected that idea during subsequent protocol submission for IRB since it was to affect the calculation of ‘incident early neonatal mortality’ to the extent that it would have rendered the calculation of that index impossible on statistical grounds.

YES

“Number of babies recruited were explicitly stated in the manuscript”

Results – [pp. 8]

Authors added the total number of babies recruited

YES

The authors did not discuss the possible hospital system factors that may be responsible for neonatal deaths which may serve as predictors or are these part of the residual factors.

Discussion – [pp. 11]

Authors included ‘hospital/centre’ as one among potential HOSPITAL SYSTEM factors. Specifically, we separately analysed each hospital. Besides, we included each of the three hospitals separately in the multivariable binary logistic regression analysis whereby Temeke regional referral hospital was taken as a reference hospital under HOSPITAL SYSTEM factor (refer to table 3)

NO

The authors should highlight the possible residual factors responsible for neonatal deaths even if the study does not capture or what comprises the residual factors Introduction – [pp. 3] By default, the definition of residual factors included ‘latent variables…’ and by default could not be explicitly stated by investigators even though potentially statistically estimated.

We wish to request the reviewer to consider the term ‘residual factors’ as per the definition proposed in the introduction section of the manuscript.

NO

Table 2. Factors should be changed to diagnoses. Results [pp. 9] Changed as per the reviewers’ recommendations YES

"Otherwise, we do believe the hypothesized ‘residual factors for early neonatal mortality’ to have a

potential for deleterious health consequences for newborns who managed to survive post-early"" What are these residual factors. The readers would like to know what makes up the residual factors and learn from it so as to provide better care for our babies

Discussion [pp. 12] Authors kindly request the reviewer to refer to the proposed definition of the term ‘residual factors’ explicitly stated in the introduction section on page 3 of the manuscript document.

By default, we hypothesized that ‘residual factors’ to be de facto latent variables. Latent variables by their very nature

cannot be stated though statistically can be estimated.

NO

Attachment

Submitted filename: REPONSES TO REVIEWERS- PONE-D-25-05428R1.doc

pone.0338497.s009.doc (53KB, doc)

Decision Letter 2

Chika Onwuamah

27 Aug 2025

Dear Dr. Leshabari,

Please submit your revised manuscript by Oct 11 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Chika Kingsley Onwuamah, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #2: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #2: No

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: No

**********

Reviewer #2: The issues raised in the previous reviews have not been satisfactorily addressed. Some vital information is missing from the manuscript such as number of live deliveries and the actual number of babies who died. The factors associated with mortality are not sufficiently elucidated; the tables are not sufficiently explicit. A lot of data said to have been collected with the CRF appeared not to have been included in the analysis, and these may have facilitated better comprehension of the study. A lot of allusion was made to "residual factors of neonatal mortality", but there appears to have been no efforts expended to discover what these factors might be.

A more detailed review is attached.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #2: No

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachment

Submitted filename: Early Neon Mort in Tanz Rev 3.docx

pone.0338497.s008.docx (15.6KB, docx)
PLoS One. 2025 Dec 11;20(12):e0338497. doi: 10.1371/journal.pone.0338497.r006

Author response to Decision Letter 3


11 Sep 2025

1. How many of the 370 admitted babies actually died: from table 2, we have a total of 175 deaths and 299 living (giving a total of 474). We are told that this is because some babies had multiple diagnoses (in the presence of multiple diagnosis, what was the primary cause of death?). However, if we took the total of 474, then 175 deaths would be 36.9%, which would be in agreement with what is reported in some literature of about a third of admitted neonates dying

Authors' responses: - Authors have re-written table no. 2 to incorporate the comparator values. Thus, the total number of newborns who died was 104 and vivid in the sum total of each reported diagnosis in the death column. We hope we have removed the unnecessary confusion to reviewer’s/readers via incorporating the comparator rows in table no. 2

- Indeed, it was erroneous to summate the gross/total numbers of deaths in table no. 2 due to existence of multiple diagnoses in some studied neonates.

e.g. about 45% of neonates who died of RDS on day 1 were also reported to have birth asphyxia immediately after birth

2. How many live births occurred in the study hospitals during the 6 months of the study? This should serve as the denominator for the neonatal mortality rate in number/1000 live births.

Authors responses: - 370 live-newborns were delivered and followed-up at study settings during the study period.

Note:

a. We excluded by design all newborns admitted in the wards but delivered at lower facilities or home prior to admission.

b. We also excluded by design all stillbirth deliveries.

3. As stated in the previous reviews, it would have been easier to use the number of deaths over the 2,212 days of follow up to give the number of deaths /100 days of follow up of neonates admitted after birth

Authors' responses: - Noted.

That is near exactly what authors did in estimating incident early neonatal death rates. However, instead of using number of deaths/100 days of follow-up of neonates admitted after birth, we rather estimated the early neonatal death rates by using number of deaths that occurred among live-births delivered at the settings in 2212 days of follow-up over (divided by) total number of live-births delivered at the study settings in 2212 days of follow-up. Thereafter, the resultant estimate was multiplied by a factor of 1000 to get the estimated early neonatal death rates per 1000-live births

- Otherwise, authors did not understand the source of the 100-days of follow-up parameter in the computation of early neonatal deaths rates.

4. The tables are difficult to interpret; for table 2 for instance, what was the comparator for birth asphyxia that gave the values: ꭓ2 of 20.4, Df of 1, and p value of 0.000. Same difficulty for all the other diagnoses. Table 3 is even more difficult for me to interpret.

Authors' responses:

- Noted and changed as per the reviewer’s advise/recommendations.

Specifically, in each neonatal diagnosis, a comparator row has been added for ease observation and calculation of both observed and expected values in the chi-square statistics. Thus, even though there are no changes in the overall numerics/message, authors considered it logical to include comparator row.

- Likewise, authors have made substantial changes to table 3 in order to facilitate easy understanding to readers. Specifically,

a. For all categorical variables that incorporated dummies, a reference category has now been included in the table.

b. Besides, a description on why some variables in table 3 are without reference values (they were treated as continuous variables) has also been justified in text.

5. A lot of the parameters said to be collected with the CRF, including maternal education, time of registration for ANC, number of ANC visits, maternal conditions like chorioamnionitis and antepartum haemorrhage (omitted were maternal hypertension and diabetes), cadre of health providers at delivery, whether babies were singletons or multiples, time to admission to neonatal unit, and so on were not included in the analysis. The addition of these parameters would have enriched the study.

Authors' responses:

- Authors have included parameters that were initially left out in the results section. They are currently justified as text either before or as numerics in table 1 and either before as text or as numerics in table 3.

- Besides, the justifications behind why some factors described in table 1(baseline characteristics) still did not appear in the final analysis has been made in text for readers/reviewers.

i.e. We included only those (maternal, neonatal or hospital-based) factors that satisfied the assumptions statistically associated with linear model fitting. Thus, for a factor to be included into the final multivariable binary logistic regression model, it had to show evidence of its residuals to be normally distributed, homoscedastic with neither significant multi-collinearity, auto-correlation nor deviation from linearity assumptions. Besides, for inclusion into the final multivariable model, its p-value must have been < 0.2 at univariate/crude statistics.

6. From the discussion, it appears the major interest of the authors are the “residual factors of neonatal mortality”. These unnamed and unknown factors are speculations at best and should properly be mentioned at the end of the discussion (not the beginning) as possible causes of the “high”mortality.

Authors' responses: Agreed and removed everything about ‘residual factors of neonatal mortality’ from the start of the discussion section and shift them to the end of the discussion section as per reviewer’s recommendations/advice

7. I still maintain that it is not sufficient to mention “residual factors which are not known but can be statistically measured”. The autors should have explored deeper to discover the reason(s) for the discrepancies in deaths among the 3 study hospitals. The design of the study should have included possible health system factors such as: are the number of healthcare workers of different cadres adequate for the patient load, are there delays in patient admission, surgical procedures, are there patient fees that may hinder provision of care, are there adequate supply of materials at all times, are there unnecessary bottle-necks that hinder prompt patient care, etc.?

Authors' responses: -Agreed and some changes made. For instance, we included the comparator/reference hospital (for comparison) in the final analysis. However, some suggested changes were not considered since:

1. All the studied hospitals are in the same hierarchy in the Tanzania’s referral health system, and being managed/supervised by the same central ministry of health, and therefore their supplies are replicate equally resources at the study settings. i.e. Amana, Mwananyamala and Temeke hospitals have all the same number of child health specialists, the same hospital protocol as well as following the same national guidelines – e.g. in Tanzania, all children under five years of age (including neonates) receive free service on a de jure basis. Thus, exploring anything that is already guaranteed by laws (and order) would attract penalties from the ethics review (IRB) boards.

2. Some of the unnecessary ‘bottlenecks’ have been hypothesized and acknowledged by authors as study limitations.

e.g. there are potential indications that ‘early neonatal deaths’ in Dar es Salaam hospitals to have ‘seasonal variation’. The fact that our study was designed for 6-months only and made to be observational by design, means exact mechanisms about causal factors were far beyond the objectives and design of this observational study.

Attachment

Submitted filename: RESPONSES TO REVIEWERS - PONE-D-25-05428R2.doc

pone.0338497.s011.doc (49.5KB, doc)

Decision Letter 3

Chika Onwuamah

29 Sep 2025

Dear Dr. Leshabari,

Please submit your revised manuscript by Nov 13 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org . When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

  • A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

  • A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

  • An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: https://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols . Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols .

We look forward to receiving your revised manuscript.

Kind regards,

Chika Kingsley Onwuamah, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

If the reviewer comments include a recommendation to cite specific previously published works, please review and evaluate these publications to determine whether they are relevant and should be cited. There is no requirement to cite these works unless the editor has indicated otherwise. 

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #2: Partly

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #2: No

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: No

**********

Reviewer #2: This manuscript has been reviewed severally and major issues identified in these reviews have not been addressed. The details are in the attached report.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #2: Yes:  Agatha N. David

**********

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/ . PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org . Please note that Supporting Information files do not need this step.

Attachment

Submitted filename: Early Neon Mort in Tanz Rev 4.docx

pone.0338497.s010.docx (16KB, docx)
PLoS One. 2025 Dec 11;20(12):e0338497. doi: 10.1371/journal.pone.0338497.r008

Author response to Decision Letter 4


16 Nov 2025

Reviewers’ comments/queries/recommendations Section

[Page number] Authors’ justifications/responses to the changes/status made Changes made

[Yes/No]

1. The result of early neonatal mortality rate (NMR) of 281/1000 live births cannot be correct.

Results

[pp. 8 ] We have made changes as per the reviewers’ recommendations/suggestions. We deleted the incident mortality figures and computed the prevalence of mortality among sick admitted newborns. Specifically, the sentence now reads as

“Besides, we also found the prevalence of deaths among followed-up babies to be 28.1% at the study sites during the study period”

Yes

2. While table 2 has been corrected, Table 3 remains a challenge. In talking about associations, it is crucial to explain what is associated with what in order to provide clinical clarity.

Results

[ pp. 10 ] We have made changes as suggested/advised by the reviewer.

Specifically, we categorized respiratory rates into 3 distinct groups namely tachypnea (RR> 60 b/min), eupnoea (RR of 40 – 60 b/min) and bradypnoea (RR < 40 b/min) and reported their estimates separately in each category

Likewise, for gestational age at delivery, we also categorized into three different groups and report their estimates accordingly.

Yes

Reviewers’ comments/queries/recommendations Section

[Page number] Authors’ justifications/responses to the changes/status made Changes made

[Yes/No]

3. They explained away the non-use of maternal and health system information said to have been collected in the CRF by using fancy statistical terms but they should find a way to incorporate and analyze all that data. The addition of these parameters will enrich the study

Results

[pp. 9 ]

We fitted a newer binary multivariable logistic regression model that was considered PARSIMONIOUS enough (with LR-goodness of fit χ2 test score of 4.61 with 4 degrees of freedom) that was considered to be linear fit for our predictor variables. However, all efforts to include those factors were rendered futile since:

1. Some failed on linearity test (e.g. birth weight) – TOLERATED but proved to be FUTILE in its predictive power.

2. Some had significant multicollinearity with the fitted linear model (e.g. number of available neonatologists, presence/absence of emergency neonatal resuscitation equipments) – NON-TOLERABLE as no LINEAR model could be estimated with precision at any level of significance tested!

3. Others displayed significant autocorrelation (e.g. time of delivery, birth order of the baby) - NON-TOLERABLE as no fitted linear model.

4. And yet others displayed significant heteroscedasticity (e.g. history of maternal fever, chorioamnionitis and antepartum haemorrhage) with the outcome variable (neonatal death = 1) – NON-TOLERABLE

Thus, whereas TOLEARANCE could be granted for VIOLATION of linearity assumption (i.e. birthweight) the rest were considered A NON-NEGOTIABLE for inclusion into the linear model as for sure they were to render the entire analysis useless due to EXTREME VIOLATION of linear model assumptions. And even though we decided to tolerate violation of linearity in order to confer reviewer’s recommendations, any sensible reader would be able to see that in table 3 – results section, since the resultant p-value on the univariate analysis were a unit (p-value = 1.000) unlike a maximum of 0.2 that were justifiably a threshold for model inclusion into the multivariable analysis. Thus, predictive power of the variable “birthweight” was almost NIL for early neonatal mortality in the fitted linear model (see table 3 on pp. 10)!

Yes

Attachment

Submitted filename: RESPONSES TO REVIEWERS - PONE-D-25-05428R4.doc

pone.0338497.s013.doc (40.5KB, doc)

Decision Letter 4

Chika Onwuamah

24 Nov 2025

<p>Predictors of early newborn deaths at Dar es Salaam public regional referral hospitals: A prospective observational hospital-based study

PONE-D-25-05428R4

Dear Dr. Leshabari,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice will be generated when your article is formally accepted. Please note, if your institution has a publishing partnership with PLOS and your article meets the relevant criteria, all or part of your publication costs will be covered. Please make sure your user information is up-to-date by logging into Editorial Manager at Editorial Manager®  and clicking the ‘Update My Information' link at the top of the page. For questions related to billing, please contact billing support .

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Chika Kingsley Onwuamah, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

Reviewer #2: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions??>

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously? -->?>

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available??>

The PLOS Data policy

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English??>

Reviewer #2: Yes

**********

Reviewer #2: The authors have satisfactorily addressed the issues raised in the previous reviews and the manuscript is now recommended for acceptance for publication.

**********

what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy

Reviewer #2: No

**********

Attachment

Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Final Rev.docx

pone.0338497.s012.docx (23KB, docx)

Acceptance letter

Chika Onwuamah

PONE-D-25-05428R4

PLOS ONE

Dear Dr. Leshabari,

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now being handed over to our production team.

At this stage, our production department will prepare your paper for publication. This includes ensuring the following:

* All references, tables, and figures are properly cited

* All relevant supporting information is included in the manuscript submission,

* There are no issues that prevent the paper from being properly typeset

You will receive further instructions from the production team, including instructions on how to review your proof when it is ready. Please keep in mind that we are working through a large volume of accepted articles, so please give us a few days to review your paper and let you know the next and final steps.

Lastly, if your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

You will receive an invoice from PLOS for your publication fee after your manuscript has reached the completed accept phase. If you receive an email requesting payment before acceptance or for any other service, this may be a phishing scheme. Learn how to identify phishing emails and protect your accounts at https://explore.plos.org/phishing.

If we can help with anything else, please email us at customercare@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Chika Kingsley Onwuamah

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Data. Minimal dataset.

    (XLS)

    pone.0338497.s001.xls (209.5KB, xls)
    Attachment

    Submitted filename: Reviewers Comment PONE-D-25-05428.docx

    pone.0338497.s002.docx (15.5KB, docx)
    Attachment

    Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Rev.docx

    pone.0338497.s003.docx (17KB, docx)
    Attachment

    Submitted filename: PONE MS Reviewer recommendation.docx

    pone.0338497.s004.docx (15KB, docx)
    Attachment

    Submitted filename: RESPONSE TO REVIEWERS.doc

    pone.0338497.s007.doc (74KB, doc)
    Attachment

    Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Rev.docx

    pone.0338497.s006.docx (15.1KB, docx)
    Attachment

    Submitted filename: REPONSES TO REVIEWERS- PONE-D-25-05428R1.doc

    pone.0338497.s009.doc (53KB, doc)
    Attachment

    Submitted filename: Early Neon Mort in Tanz Rev 3.docx

    pone.0338497.s008.docx (15.6KB, docx)
    Attachment

    Submitted filename: RESPONSES TO REVIEWERS - PONE-D-25-05428R2.doc

    pone.0338497.s011.doc (49.5KB, doc)
    Attachment

    Submitted filename: Early Neon Mort in Tanz Rev 4.docx

    pone.0338497.s010.docx (16KB, docx)
    Attachment

    Submitted filename: RESPONSES TO REVIEWERS - PONE-D-25-05428R4.doc

    pone.0338497.s013.doc (40.5KB, doc)
    Attachment

    Submitted filename: Predictors of Early Neon Mort in Dar es Salaam Final Rev.docx

    pone.0338497.s012.docx (23KB, docx)

    Data Availability Statement

    All relevant data are within the paper and its Supporting information files.


    Articles from PLOS One are provided here courtesy of PLOS

    RESOURCES