Skip to main content
PLOS Medicine logoLink to PLOS Medicine
. 2021 May 5;18(5):e1003610. doi: 10.1371/journal.pmed.1003610

Components of clean delivery kits and newborn mortality in the Zambia Chlorhexidine Application Trial (ZamCAT): An observational study

Jason H Park 1,*, Davidson H Hamer 2,3, Reuben Mbewe 4, Nancy A Scott 2, Julie M Herlihy 5, Kojo Yeboah-Antwi 6, Katherine E A Semrau 7,8,9
Editor: Jenny E Myers10
PMCID: PMC8133479  PMID: 33951036

Abstract

Background

Neonatal infection, a leading cause of neonatal death in low- and middle-income countries, is often caused by pathogens acquired during childbirth. Clean delivery kits (CDKs) have shown efficacy in reducing infection-related perinatal and neonatal mortality. However, there remain gaps in our current knowledge, including the effect of individual components, the timeline of protection, and the benefit of CDKs in home and facility deliveries.

Methods and findings

A post hoc secondary analysis was performed using nonrandomized data from the Zambia Chlorhexidine Application Trial (ZamCAT), a community-based, cluster-randomized controlled trial of chlorhexidine umbilical cord care in Southern Province of Zambia from February 2011 to January 2013. CDKs, containing soap, gloves, cord clamps, plastic sheet, razor blade, matches, and candle, were provided to all pregnant women. Field monitors made a home-based visit to each participant 4 days postpartum, during which CDK use and newborn outcomes were ascertained. Logistic regression was used to study the association between different CDK components and neonatal mortality rate (NMR). Of 38,579 deliveries recorded during the study, 36,996 newborns were analyzed after excluding stillbirths and those with missing information. Gloves, cord clamps, and plastic sheets were the most frequently used CDK item combination in both home and facility deliveries. Each of the 7 CDK components was associated with lower NMR in users versus nonusers. Adjusted logistic regression showed that use of gloves (odds ratio [OR] 0.33, 95% CI 0.24–0.46), cord clamp (OR 0.51, 95% CI 0.38–0.68), plastic sheet (OR 0.46, 95% CI 0.34–0.63), and razor blade (OR 0.69, 95% CI 0.53–0.89) were associated with lower risk of newborn mortality. Use of gloves and cord clamp were associated with reduced risk of immediate newborn death (<24 hours). Reduction in risk of early newborn death (1–6 days) was associated with use of gloves, cord clamps, plastic sheets, and razor blades. In examining perinatal mortality (stillbirth plus neonatal death in the first 7 days of life), similar patterns were observed. There was no significant reduction in risk of late newborn mortality (7–28 days) with CDK use. Study limitations included potential recall bias of CDK use and inability to establish causality, as this was a secondary observational study.

Conclusions

CDK use was associated with reductions in early newborn mortality at both home and facility deliveries, especially when certain kit components were used. While causality could not be established in this nonrandomized secondary analysis, given these beneficial associations, scaling up the use of CDKs in rural areas of sub-Saharan Africa may improve neonatal outcomes.

Trial registration

Name of trial: Zambia Chlorhexidine Application Trial (ZamCAT) Name of registry: Clinicaltrials.gov Trial number: NCT01241318.


Jason Park and co-workers assess components of clean delivery kits for possible contributions to reduced newborn mortality in a trial done in Zambia.

Author summary

Why was this study done?

  • Infection during childbirth is a major cause of newborn mortality and morbidity in rural and resource-limited settings.

  • Clean delivery kits can prevent pathogen transmission during infection by providing sterile equipment and encouraging hygienic behaviors.

  • A more nuanced understanding of the benefits of clean delivery kits and their components would aid global implementation to help reduce newborn mortality.

What did the researchers do and find?

  • We analyzed the data from the Zambia Chlorhexidine Application Trial (ZamCAT), a cluster-randomized controlled trial conducted in Zambia in 2011–2013.

  • During ZamCAT, we provided clean delivery kits to all mothers in the community and tracked the health outcomes of all women and newborns through the neonatal period.

  • Analysis of 38,579 deliveries showed us that use of gloves, cord clamps, plastic sheets, and razor blades during intrapartum care were associated with lower newborn mortality, in both home and facility deliveries.

  • Components of clean delivery kits were associated with lower risk of perinatal and newborn mortality in the first 7 days of life, but not with mortality between 7 and 28 days of life.

What do these findings mean?

  • Components of clean delivery kits that showed highest usage and association with newborn mortality reduction should be included in future clean delivery kit interventions.

  • As this is a post hoc secondary data analysis and the trial was not meant to specifically study the impact of clean delivery kits, causality cannot be inferred.

  • Nevertheless, the large sample size, variation in component use, and study design focused on community settings provide support for clean delivery kits as an intervention that may improve newborn health outcomes in both home and facility deliveries.

Introduction

Despite progress in decreasing child mortality between 1990 and 2015, reductions in neonatal mortality have been slower, remaining unacceptably high at 2.9 million deaths globally each year [1,2]. Infection is one of the leading causes of neonatal death—responsible for up to 35% of neonatal deaths—and 30%–40% of neonatal infections are from pathogens acquired from the mother or environment during labor and delivery leading to neonatal sepsis [35]. A disproportionate amount of this burden occurs in low- and middle-income countries.

In order to prevent infection at birth and reduce maternal and neonatal mortality, the World Health Organization (WHO) promotes clean delivery practices through the observance of “six cleans” at the time of delivery: clean hands, perineum, surface, cord cutting and tying, and nothing unclean introduced into the vagina [6]. Clean delivery kits (CDKs) include tools such as soap, gloves, cord ties, and other sterile equipment to enable the “six cleans,” offering a potential low-cost intervention to facilitate clean delivery practices [7]. Studies assessing the impact of CDK use have shown a consistent increase in clean delivery practices [810]. Studies in South Asia where CDKs were part of a bundle of interventions demonstrated their efficacy in significantly reducing perinatal and neonatal mortality [11,12]. Given the additional evidence for protection against cord infection and neonatal tetanus, CDKs appear to be an effective intervention to help reduce neonatal morbidity and mortality [9,13].

Despite evidence of the CDKs’ benefit for newborn health, there are limitations to our current knowledge of their impact. First, there have been few studies of differences in impact of CDK use on immediate, early, and late neonatal mortality. CDK use may have protective effects beyond immediate infection control as CDKs have been associated with reductions in complications from neonatal prematurity [11,12]. Thus, a more comprehensive time to event analysis could elucidate the role of CDKs in preventing varied conditions during the early newborn period. Second, previous studies noted differences in CDK components used in home as opposed to facility deliveries, but there is no published information about the value each component has in improving neonatal outcomes [10]. Finally, there have not been large-scale studies assessing the impact of CDKs in sub-Saharan Africa. The most robust literature to date has come from South Asia and the Middle East [1113]. It is reasonable to expect that geographic, demographic, and cultural differences, such as home delivery rates and practices, antenatal care service usage, and prevalence of maternal HIV, are important covariates that may influence perinatal outcomes in sub-Saharan Africa.

Understanding the differential impact of the CDK components and population characteristics that can affect the efficacy of CDKs can inform future program design to implement CDKs. Utilizing data from the Zambia Chlorhexidine Application Trial (ZamCAT), a cluster-randomized controlled trial examining the impact of topical application of 4% chlorohexidine on the cord stump in reducing rates of neonatal mortality in Southern Province of Zambia [14], we investigated the relationship between the individual components of CDKs and neonatal health outcomes for home and facility deliveries.

Methods

Study design

ZamCAT was a community-based, cluster-randomized controlled trial in Southern Province, Zambia, that investigated the impact of daily cord care with 4% chlorohexidine on reducing severe omphalitis and neonatal mortality compared to dry cord care. The ZamCAT design and methods have been reported elsewhere; the study was conducted from February 2011 to January2013 [15]. In the main intent-to-treat and per-protocol analyses, 4% chlorhexidine did not reduce neonatal mortality compared to dry cord care [14]. The present analysis was not in the prespecified analysis plan but was not data-driven. For this secondary, post hoc analysis, the data were pooled across randomization from the initial arms of the study design.

Study population

The trial was implemented in 6 of the 11 districts in Southern Province—Mazabuka, Siavonga, Monze, Choma, Kalomo, and Livingstone. The study locations included a wide range of health facilities, both urban and rural, in 90 facility catchment areas across the 6 districts. Eligible healthcare centers were Zambian government or mission primary healthcare centers providing routine antenatal services and conducting a minimum of 160 births per year.

At the time of the study, the most recent Zambia Demographic and Health Survey report in 2007 estimated a neonatal mortality rate (NMR) at 34 per 1,000 live births [16]. While more than 90% of pregnant women had an initial registration at an antenatal clinic, only 60% had 4 or more antenatal visits. In Southern Province, 62% of the deliveries occurred at home, 99.3% of which were attended by nonskilled providers, including traditional birth attendants, untrained family, or community members [16]. In comparison, 96.6% of deliveries at health facilities were attended by skilled providers including doctors, clinical officers, midwives, and nurses.

Eligibility and enrollment

The study field monitors screened women attending antenatal care visits at eligible health centers and during community outreach activities for study enrollment. Eligible women were in their second or third trimester, aged 15 years or older, planned to stay in the catchment area until 28 days postpartum, and provided informed consent. At enrollment, data such as expected date of delivery and demographic information were collected. Participants were encouraged to deliver at their nearest health facility and were given standard newborn care messages per national guidelines including information about delivery location, breastfeeding, cord care, and danger signs of ill health in their newborn baby. Further information on enrollment procedures is reported elsewhere [15].

Study procedures

Field monitors made 5 home visits—1 antenatal and 4 postnatal (day 1, 4, 10, and 28 postpartum). The antenatal visit was completed within 2 weeks of enrollment, during which the field monitor confirmed the home location for follow-up, reviewed study procedures with the mother, and screened for pregnancy danger signs. During this initial antenatal visit, field monitors provided a standard CDK to all study participants, regardless of randomization assignment. The CDK, developed in coordination with the Zambia Ministry of Health, contained a bar of soap, sterile razor blade, sterile gloves, 2 cord clamps, candle, matches, and a plastic sheet. The cost of each CDK was about US$5.50. At each of the 4 postnatal visits, field monitors assessed and documented the mother’s and newborn baby’s health status. At the day 4 postpartum visit, the field monitors asked the mother about use of each component of the CDK. Any mother or newborn baby with danger signs or symptoms, as defined by WHO’s signs of newborn possible severe bacterial infection [17], was referred to the healthcare center.

Variables and outcomes

Each of the 7 CDK components was categorized as a binary variable depending on whether it was used or not, based on maternal self-report at the day 4 postpartum visit. With 7 CDK components, there were 128 potential combinations of use. Every combination of CDK component use was tallied to extract the most common combinations, stratified by delivery location. Delivery location was categorized as “facility” if it was a hospital or health facility, or “home” if otherwise. Maternal age and education were captured. Newborn gestational age was calculated based on weeks since last menstrual period at enrollment and weeks from enrollment to birth. Gestational age was dropped if less than 0 or greater than 42 weeks. Gestational age at birth and birth weight were categorized according to WHO’s classification: term (>37 weeks), preterm (32–37 weeks), very preterm (28–31 weeks), and extremely preterm (<28 weeks), and normal birth weight (>2.5 kg), low birth weight (1.5–2.5 kg), and very low birth weight (<1.5 kg) [18,19].

In this analysis, the primary outcome is all-cause neonatal mortality within 28 days postpartum. Deaths were documented by interview with the mother; stillbirth was defined as an infant who did not breathe, cry, or move at the time of delivery. In case of death, verbal autopsies were completed including information on the time of birth, death, and surrounding circumstances. Trained clinicians reviewed the verbal autopsy reports and determined the cause of death. The timing of newborn death was categorized as immediate if in the first 24 hours of life, early if at 1 to 6 days of life, and late if at 7 to 28 days of age [20]. NMR for each CDK component was calculated by using the number of newborn deaths stratified by usage of each CDK component. This was a descriptive exercise, and the statistical significance of differences in NMR was not calculated as the sample size of nonusers of specific CDK components was too low. Similarly, we examined perinatal mortality (stillbirth plus neonatal death in the first 7 days of life) and conducted the analysis in the same manner as described above for neonatal mortality. Signs of infection such as baby’s temperature, convulsions/fits, or lack of movement without stimulus were assessed by field monitors at each postnatal visit. For rates of presence of infection danger signs, newborns were censored if their age of death occurred prior to the field monitor visit for assessment.

Data analysis/statistical methods

This is a post hoc secondary analysis of data collected in ZamCAT, a cluster-randomized controlled trial. We decided to do this additional analysis for 2 reasons. First, we wanted to understand the uptake and use of CDKs in the population studied during the trial. Second, we wanted to assess the associations between kit use and the health outcomes of newborns.

The main study targeted enrollment of 42,570 women; we used the full cohort for this secondary analysis of the impact of CDK use on neonatal mortality, as the main study did not see a difference in newborn outcomes between the study and control arms [14,15]. Complete case analysis was used, and cases with missing delivery location, CDK use, and newborn outcome were excluded from analysis. We initially excluded stillbirths from the analysis as CDKs would not have had any effect on deaths that occurred antepartum and CDKs may have been less likely to be used if fetal demise was noted or suspected prior to labor. To understand the potential impact on intrapartum stillbirths and address potential misclassification with early neonatal death, we assessed perinatal mortality as an outcome. Bivariate logistic regression was used to compare proportions of neonatal deaths stratified by each CDK component, delivery location (home versus facility), and immediate/early (0–6 days of age) versus late (7–28 days of age) mortality. Each of the 128 permutations of the 7 CDK components was analyzed by frequency of use. The 5 most frequently used combinations at home and facility deliveries were analyzed for their NMR. Baseline characteristics chosen as key covariates were based on the main study, with a focus on known risk factors for newborn sepsis and mortality, including newborn sex, low birth weight, prematurity, maternal age, and maternal education [14]. Given the parent study, chlorohexidine application was considered as a covariate. However, we excluded chlorhexidine use due to survivor bias as ongoing chlorohexidine application was dependent on newborn survival.

Data analysis was performed using Stata 15. The main study was registered at ClinicalTrials.gov (NCT01241318).

Ethical approval

The Boston University Medical Campus Institutional Review Board (protocol #H-29647) and University of Zambia Research Ethics Committee (protocol #016-08-10) provided ethical approval, and the Zambia Ministry of Health approved the study. All women provided written informed consent, which was obtained in either English or Tonga.

Results

Study population

There were 38,579 deliveries recorded during the study. Deliveries with missing information on CDK use, newborn outcome, or delivery location were excluded from analysis (n = 960 deliveries). For the primary analysis, 623 stillbirths were removed, resulting in 36,996 newborns from 36,606 women for analysis (Fig 1). Women were on average 25.6 years old; 83% were married, and 63.6% delivered at a hospital or a health facility (Table 1). Overall NMR was 14 deaths per 1,000 live births, approximately half of which occurred within the first 24 hours after birth. NMR was similar across delivery location (home or facility). While not all descriptive information was available for the excluded participants, overall demographics were similar to those of the included participants.

Fig 1. Participant flow chart.

Fig 1

CDK, clean delivery kit.

Table 1. Participant characteristics.

Mother characteristics Number of women (n = 36,606) Excluded women (n = 1,583)
Age (years)
    Less than 20 8,519 (23.3%) 357 (22.6%)
    20–29 17,548 (47.9%) 670 (42.3%)
    30–39 9,079 (24.8%) 422 (26.7%)
    40 or more 1,460 (4.0%) 134 (8.5%)
Marital status
    Married 30,190 (82.5%) 1240 (78.3%)
    Formerly married 563 (1.5%) 23 (1.5%)
    Other 5,665 (15.5%) 255 (16.1%)
    No response 188 (0.5%) 65 (4.1%)
Education
    Did not finish primary school 22,566 (61.7%) 968 (61.2%)
    Finished primary but not secondary school 13,533 (37.0%) 538 (34.0%)
    Finished secondary school or more 303 (0.8%) 11 (0.7%)
    No response 204 (0.6%) 66 (4.2%)
Delivery location
    Hospital 4,954 (13.5%) 240 (30.2%)
    Health center 18,343 (50.1%) 280 (35.2%)
    Home 13,005 (35.5%) 259 (32.5%)
    Other 304 (0.8%) 17 (2.1%)
Newborn characteristics Number of newborns (n = 36,996) Excluded newborns (n = 1,583)
Birth sex
    Male 18,170 (49.1%) 675 (55.6%)
    Female 18,532 (50.1%) 540 (44.4%)
    No response 294 (0.8%) 0 (0.0%)
Estimated gestational age
    Term (>37 weeks) 27,828 (75.2%) 1142 (72.1%)
    Preterm (32–37 weeks) 7,718 (20.9%) 299 (18.9%)
    Very preterm (28–31 weeks) 1,002 (2.7%) 82 (5.2%)
    Extremely preterm (<28 weeks) 448 (1.2%) 60 (3.8%)
Birth weight
    Normal (>2.5 kg) 35,338 (95.5%) 1554 (98.2%)
    Low (1.5–2.5 kg) 1,587 (4.3%) 27 (1.7%)
    Very low (<1.5 kg) 71 (0.2%) 2 (0.1%)

CDK use

CDK use was nearly universal; at least 1 component was used in 99.3% of deliveries, and at least 4 of the 7 components were used in 89.9% of deliveries. All 7 components were used in 28.1% of deliveries. Gloves, cord clamp, plastic sheet, and razor blade were the most frequently used components (Table 2). Women who delivered at home were more likely to have used the soap, razor blade, candle, and matches, while women who delivered in facilities were more likely to have used the cord clamp than those who delivered at home. Gloves, cord clamp, and plastic sheet were used together in the 5 most common combinations of CDK use across all locations, accounting for 85.9% of all combinations (Table 3). The razor blade was used in the top 5 most common CDK combinations at home deliveries, and was used in the top 3 most common CDK combinations among facility deliveries.

Table 2. CDK use by component.

CDK component Component use, n (%) NMR (deaths/1,000 live births) at all delivery locations
All delivery locations (n = 36,996) Home (n = 13,412) Facility (n = 23,584) Component use Component nonuse
Soap 27,422 (74.1%) 11,491 (85.7%) 15,931 (67.6%) 11.4 21.7
Gloves 35,858 (96.9%) 13,029 (97.1%) 22,829 (96.8%) 11.9 84.4
Cord clamp 34,795 (94.1%) 11,851 (88.4%) 22,944 (97.3%) 11.7 51.3
Plastic sheet 35,478 (95.9%) 13,176 (98.2%) 22,302 (94.6%) 11.8 67.2
Razor blade 32,453 (87.7%) 13,087 (97.6%) 19,366 (82.1%) 11.3 33.7
Candle 12,802 (34.6%) 7,321 (54.6%) 5,481 (23.2%) 10.3 16.1
Matches 12,588 (34.0%) 7,250 (54.1%) 5,338 (22.6%) 10.2 16.1

CDK, clean delivery kit; NMR, neonatal mortality rate.

Table 3. CDK use by most common combinations.

Most frequent CDK combinations Soap Gloves Cord clamp Plastic sheet Razor blade Candle Matches Percent used (%) NMR (deaths/1,000 live births)
All delivery locations
1 Yes Yes Yes Yes Yes No No 36.7 11
2 Yes Yes Yes Yes Yes Yes Yes 28.1 10
3 No Yes Yes Yes Yes No No 12.8 13
4 No Yes Yes Yes No No No 4.7 15
5 Yes Yes Yes Yes No No No 3.7 17
Home deliveries
1 Yes Yes Yes Yes Yes Yes Yes 43.3 8
2 Yes Yes Yes Yes Yes No No 31.6 10
3 No Yes Yes Yes Yes No No 6.0 16
4 Yes Yes No Yes Yes Yes Yes 4.3 7
5 No Yes Yes Yes Yes Yes Yes 3.9 10
Facility deliveries
1 Yes Yes Yes Yes Yes No No 39.5 12
2 Yes Yes Yes Yes Yes Yes Yes 19.5 13
3 No Yes Yes Yes Yes No No 16.7 12
4 No Yes Yes Yes No No No 7.2 14
5 Yes Yes Yes Yes No No No 5.4 16

CDK, clean delivery kit; NMR, neonatal mortality rate.

The difference in NMR (deaths per 1,000 live births) between use and nonuse of each CDK component showed a reduction in risk for each of the CDK components individually. The greatest NMR reductions were seen for the use of the gloves (nonuse: 84.4 deaths per 1,000 live births; use: 11.9 deaths per 1,000 births), cord clamp (nonuse: 51.3 deaths per 1,000 live births; use: 11.7 deaths per 1,000 live births), and plastic sheet (nonuse: 67.2 deaths per 1,000 live births; use: 11.8 deaths per 1,000 live births) (Table 2). Similar results were found when examining the association of CDK use with perinatal mortality. There was a perinatal mortality reduction seen for use relative to nonuse of gloves, cord clamps, plastic sheets, and razor blades (S1 Table). Unadjusted, descriptive data showed that mothers who were younger and highly educated had lower NMR. Newborn characteristics associated with higher NMR included male sex, lower gestational age, and lower birth weight.

Unadjusted and adjusted logistic regression models

Unadjusted logistic regression showed strong independent relationships between use of gloves, cord clamp, plastic sheet, and razor blade and lower rates of newborn death across all delivery locations. Home deliveries especially had lower rates of newborn death when there was use of gloves, plastic sheets, and razor blades. In facility deliveries, use of gloves, cord clamp, and plastic sheet were each associated with lower likelihood of newborn mortality.

Logistic regression adjusted for other risk factors for newborn mortality showed similar associations of CDK component use with newborn mortality, with gloves, cord clamp, plastic sheet, and razor blade being the most protective CDK components across all delivery locations. Home deliveries benefited from the use of gloves, plastic sheet, and razor blade, while facility deliveries still incurred protective benefits from the gloves, cord clamp, and plastic sheet when adjusted for covariates. Covariates such as newborn male sex and prematurity showed associations with higher rates of newborn mortality. Mothers aged between 20 and 29 years old were less likely to have newborn deaths compared to mothers under 20 years of age (Table 4).

Table 4. Adjusted logistic regression—association between CDK components and newborn mortality stratified by delivery location.

 Variable All deliveries Home deliveries Facility deliveries
OR 95% CI p-Value OR 95% CI p-Value OR 95% CI p-Value
CDK component
    Soap 0.94 0.75–1.16 0.56 0.69 0.46–1.03 0.07 1.02 0.79–1.32 0.89
    Gloves 0.33 0.24–0.46 <0.001 0.49 0.26–0.93 0.03 0.38 0.25–0.59 <0.001
    Cord clamp 0.51 0.38–0.68 <0.001 0.81 0.51–1.28 0.36 0.32 0.21–0.51 <0.001
    Plastic sheet 0.46 0.34–0.63 <0.001 0.30 0.15–0.60 0.001 0.62 0.42–0.90 0.01
    Razor blade 0.69 0.53–0.89 0.004 0.31 0.17–0.58 <0.001 0.83 0.62–1.13 0.23
    Candle 1.32 0.57–3.04 0.52 1.12 0.31–4.57 0.80 1.55 0.56–4.31 0.40
    Matches 0.62 0.27–1.45 0.27 0.58 0.15–2.22 0.43 0.64 0.23–1.82 0.40
Maternal age (years)            
    Less than 20 Ref     Ref     Ref    
    20–29 0.62 0.50–0.77 <0.001 0.57 0.38–0.85 0.006 0.63 0.49–0.82 0.001
    30–39 0.84 0.66–1.07 0.17 0.68 0.43–1.07 0.09 0.92 0.69–1.24 0.60
    40 or more 1.16 0.76–1.78 0.50 1.13 0.59–2.18 0.71 1.04 0.58–1.91 0.88
Maternal education                  
    Did not finish primary school Ref   Ref   Ref  
    Finished primary but not secondary school 1.11 0.91–1.34 0.30 0.82 0.56–1.20 0.31 1.24 0.99–1.55 0.06
    More than secondary school 0.52 0.13–2.12 0.36 N/A N/A N/A 0.59 0.14–2.43 0.47
    No response 1.57 0.59–4.17 0.36 1.53 0.31–7.42 0.60 1.88 0.52–6.70 0.33
Sex of child            
    Female Ref     Ref     Ref    
    Male 1.42 1.19–1.70 <0.001 1.44 1.05–1.98 0.03 1.40 1.12–1.74 0.003
Newborn birth weight                  
    Normal Ref   Ref   Ref  
    Low birth weight 1.21 0.86–1.70 0.27 1.47 0.58–3.76 0.42 1.24 0.86–1.80 0.24
    Very low birth weight 2.54 0.93–6.96 0.07 N/A N/A N/A 2.74 0.98–7.70 0.06
Newborn estimated gestational age                  
    Term Ref   Ref   Ref  
    Preterm 1.75 1.41–2.16 <0.001 2.30 1.60–3.30 <0.001 1.44 1.11–1.90 0.007
    Very preterm 6.82 5.13–9.08 <0.001 10.62 6.84–16.50 <0.001 5.09 3.45–7.52 <0.001
    Extremely preterm 9.02 6.22–13.07 <0.001 4.40 1.81–10.66 0.001 11.24 7.41–17.07 <0.001

ORs are adjusted for known risk factors for newborn mortality. Significant p-values in bold.

CDK, clean delivery kit; N/A, not applicable; OR, odds ratio.

The adjusted logistic regression model for perinatal mortality showed an association between lower odds of perinatal mortality and use of gloves, cord clamps, plastic sheets, and razor blades at all delivery locations. When stratified by delivery location, home deliveries had an association between lower risk of perinatal mortality and use of cord clamps, plastic sheets, and razor blades. Facility deliveries had an association between cord clamp use and reduced perinatal mortality risk. Other covariates’ associations with perinatal mortality were similar to the newborn mortality associations. The only exception was birth weight: Low birth weight was not associated with increased perinatal mortality. However, 99.7% of the stillbirths were normal weight (S2 Table).

When danger signs of newborn infection were assessed, 397/36,996 newborns (1%) had infection danger signs at day 1, 141/36,642 (0.4%) at day 4, 153/36,566 (0.4%) at day 10, and 130/36,478 (0.4%) at day 28. Multivariable logistic regression did not show any significant associations between signs of newborn infection at days 1, 4, 10, and 28 and CDK components or any of the covariates.

Association of timing of death with CDK component use

Unadjusted and adjusted logistic regression models showed a reduced odds of immediate newborn death when gloves (odds ratio [OR] 0.47, 95% CI 0.24–0.91) and cord clamp (0.57, 95% CI 0.32–0.99) were used. Reduction in early newborn death was associated with use of gloves (OR 0.26, 95% CI 0.16–0.39), cord clamp (OR 0.41, 95% CI 0.28–0.60), plastic sheet (OR 0.37, 95% CI 0.24–0.55), and razor blade (OR 0.59, 95% CI 0.40–0.85). In contrast, no individual component of CDK use had a significant association with late newborn death (Table 5). Adjusted logistic regression confirmed similar associations between CDK components and timing of death. The associations between immediate/early newborn death with prematurity, birth weight, and male sex remained (p < 0.05).

Table 5. Adjusted association between timing of death and the use of clean delivery kit (CDK) components.

OR 95% CI p-value NMR Users (deaths/1,000 live births) NMR Non-users (deaths/1,000 live births)
Immediate death (less than 24 hours)
Soap 0.85 0.58–1.23 0.38 3.5 6.1
Gloves 0.47 0.24–0.91 0.03 3.8 14.9
Cord clamp 0.57 0.32–0.99 0.05 3.8 10.4
Plastic sheet 0.81 0.43–1.54 0.52 3.8 11.9
Razor blade 0.85 0.54–1.35 0.49 3.7 7.7
Candles 0.35 0.05–2. 56 0.30 2.0 5.3
Matches 1.19 0.16–8.82 0.86 2.1 5.2
Early death (between 1 and 7 days)
Soap 0.89 0.64–1.22 0.46 4.7 12.3
Gloves 0.26 0.16–0.39 <0.001 4.8 65.1
Cord clamp 0.41 0.28–0.60 <0.001 4.8 37.2
Plastic sheet 0.37 0.24–0.55 <0.001 4.9 49.3
Razor blade 0.59 0.40–0.85 0.01 4.6 21.5
Candles 1.67 0.52–5.29 0.39 4.8 7.7
Matches 0.59 0.18–1.90 0.38 4.7 7.7
Late death (between 7 and 28 days)
Soap 1.12 0.71–1.78 0.62 3.2 3.5
Gloves 0.79 0.31–2.07 0.64 3.2 5.7
Cord clamp 1.02 0.47–2.21 0.96 3.2 4.3
Plastic sheet 0.55 0.26–1.18 0.12 3.2 7.0
Razor blade 0.74 0.43–1.30 0.30 3.1 4.8
Candles 2.46 0.62–9.71 0.20 3.5 3.2
Matches 0.50 0.13–2.00 0.33 3.4 3.2

*Adjusted with known risk factors for newborn mortality

Cause of death data from verbal autopsy were available for 274 of the 521 newborn deaths. The most common cause overall was newborn sepsis, responsible for 88 (32.1%) of the autopsied newborn mortality, with infectious causes, including pneumonia, tetanus, meningitis, and diarrhea, responsible for 109 newborn deaths (39.8%). In the first 24 hours of life, perinatal asphyxia was the leading cause of death, at 49 (33.8%), with all infections combining for 34 (23.4%) deaths in this period. Between days 1 and 6 of life, infections were the leading cause of death, causing 40 (48.8%) of newborn deaths. Infections caused a further 35 newborn deaths (74.4%) between 7 and 28 days and were the leading cause of death among autopsied newborns.

Discussion

Our analysis showed that components of CDK were associated with reductions in NMR for use of each component of CDK compared to nonuse. More than 99% of women reported using at least 1 CDK component. We found a high usage (>80%) of certain CDK components including gloves, cord clamps, plastic sheets, and razor blades. In fact, 81% of deliveries used all 4 of those components. There was a significantly lower odds of newborn mortality individually associated with the use of each of these 4 CDK components, in both home and facility deliveries. Use of gloves and cord clamp were associated with lower odds of newborn mortality in the first 24 hours of life, while use of gloves, cord clamp, plastic sheet, and razor blade were associated with lower odds of newborn death in the first 7 days of life.

There were differences in the CDK components used between home and facility deliveries, with the rates of CDK use at home generally higher than at facilities. This could be due to the presence of alternative equipment at facilities; presence of hand sanitizing supplies and sterilized scissors would exclude the need to use the CDK components soap and razor blade, respectively. Similarly, candles and matches may not be needed if the childbirth occurred during daytime or if the facility had robust electrical infrastructure.

Despite the guidelines pushing for more facility deliveries in Zambia, lack of equipment at health facilities continues to pose a barrier to clean deliveries [21]. At the time of this study, only half of health facilities in Southern Province had access to soap, and only 3% to sterile gloves [22]. Supplying CDKs may be a low-cost intervention that can overcome this supply challenge for both home and facility births. A review by Bhutta et al. of existing cost-effective interventions to reduce global newborn mortality identified CDKs as an intrapartum intervention for promoting clean delivery practices [23].

Each CDK component associated with lower newborn mortality has a reasonable explanation that aligns with WHO’s “six cleans,” which doubled as their rationale for their inclusion in the CDK. Gloves improve hand hygiene, sterile cord clamp and razor blade provide clean cord care, and the plastic sheet makes for a clean birthing environment. Seward et al. showed that clean delivery practices associated with lower newborn mortality in Southeast Asia included use of boiled thread to tie the cord, boiled blade to cut the cord, and plastic sheet [12]. The CDK components in our analysis that were associated with reduced newborn mortality corresponded to these practices, providing credence to the mechanism of their benefit.

Our analysis did not find a significant association between CDK use or other covariates and infection danger signs measured in the first 28 days. This discrepancy may have been due to the rarity of reported danger signs, or subjective and inconsistent measurements of the infection danger signs. Possible inconsistencies in danger sign recording include newborn temperature documentation without thermometer confirmation or signs of mild illness mistakenly documented as signs of life-threatening systemic bacterial infection. It is also possible that if the danger signs were recorded on a postnatal visit after newborn death but still categorized in the same time frame as newborn death—immediate, early, or late—a correlation between the 2 variables would have been compromised. This emphasizes the importance of systemically robust measurements of danger signs in research in global settings.

A major strength of this study is the large sample size, which allowed differentiating between the granular effects of each CDK component. In addition, the trial design focused on the community setting, where a large proportion of women deliver and where newborn mortality from infections remains high but is relatively understudied compared to in major hospitals. This allowed us to study the impact of the interventions in a setting where the participants’ choices would mirror their regular behavior, giving us confidence that CDKs may be beneficial whether mothers deliver at home or facilities. The community design also allowed long-term follow-up, with information up to 28 days after the delivery being useful for assessing the impact of CDKs in later infections.

There were a few noteworthy limitations to this study. The use of CDK components was self-reported and collected 4 days after birth, which subjected it to recall bias. Frequent visits by the field monitors were designed to minimize recall bias. The potential that mothers with negative newborn outcomes might not remember their use of CDKs could have led to an inaccurate association between CDK use and newborn mortality. A reverse causality bias is also possible: Childbirth with negative outcomes may require focus on emergent care or aspects other than clean delivery, leading to lower CDK use. Lastly, the original study was not designed to investigate the impact of CDK and thus cannot establish causality for each CDK component. The rate of uptake of CDK was high, and the number of nonusers of each component of CDK was relatively minimal. Nonetheless, the large sample size and differences in NMR support the association between CDK use and reduced newborn mortality in both home and facility deliveries.

While this analysis was based on a dataset from rural Zambia, the mechanism of impact of CDKs may be applicable to other rural settings where home deliveries are prevalent, or health facilities have inconsistent supply of sterile delivery equipment. The effect of CDKs on newborn mortality in the first 7 days should also be generalizable to other settings; although specific microbe composition may vary by location, sterile delivery practices enforced by CDKs would still be effective. For future steps, microbiological examination of newborn infection may be helpful in discerning why there was a greater reduction in infection risk in the first 7 days compared to between 7 and 28 days, and how to reduce newborn mortality in the later newborn stages. In addition, despite evidence that the use of CDKs can also reduce maternal risk of puerperal sepsis, a systematic analysis by Hundley et al. showed that currently there is scant literature on CDKs’ impact on maternal morbidity and mortality [24,25]. Finally, a study in Pakistan showed that supplying interventions including CDKs directly to women had varied compliance to the correct use of the equipment and did not reduce newborn mortality [26]. Further studies are required to develop the most effective methods of supplying CDKs to improve adherence to best practices and increase use of components such as cord clamps, which were used less at homes than facilities despite being associated with reductions in risk of newborn and perinatal mortality.

In summary, this analysis demonstrated an association between CDK use and reduction of newborn mortality in a rural setting in sub-Saharan Africa. Utilizing a uniquely large dataset of almost 37,000 newborn outcomes, we found that, among the CDK components, use of gloves, cord clamps, plastic sheets, and razor blades were associated with lower NMR. Our analysis demonstrated a significant association between CDK use and improved newborn outcomes in the first 7 days of life. Given these positive associations, scaling up CDKs may be an effective strategy to reduce the burden of newborn mortality.

Supporting information

S1 CONSORT Checklist

(DOC)

S1 Table. Clean delivery kit (CDK) use by component and perinatal mortality rate.

(DOCX)

S2 Table. Adjusted logistic regression—association between clean delivery kit (CDK) components and perinatal mortality stratified by delivery location.

(DOCX)

S3 Table. Adjusted association between timing of newborn death and the use of clean delivery kit (CDK) components—with covariates.

(DOCX)

Acknowledgments

Research reported in this publication was supported by the Fogarty International Center and National Institute of Mental Health. We would like to thank the ZamCAT field office including the field monitors and the administrative, training, and data management team members, and the members of the data and safety monitoring board and technical advisory group. We are deeply appreciative of the support from the Ministry of Health, Southern Province Medical Office, District Medical Offices, and Chiefs of Southern Province. Finally, we would like to thank the women, their newborns, and their families for their participation and dedication to the study.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Abbreviations

CDK

clean delivery kit

NMR

neonatal mortality rate

OR

odds ratio

WHO

World Health Organization

ZamCAT

Zambia Chlorhexidine Application Trial

Data Availability

The data is available at Boston University's data repository: https://open.bu.edu/handle/2144/42348.

Funding Statement

Bill & Melinda Gates Foundation (Global Health Grant Number OPPGH5298, https://www.gatesfoundation.org/) funded DH. Fogarty International Center (Award Number D43 TW010543, https://www.fic.nih.gov/) funded JP. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

References

  • 1.You D, Wardlaw T, Newby H, Anthony D, Rogers K. Renewing the promise of survival for children. Lancet. 2013;382(9897):1002–04. 10.1016/S0140-6736(13)61895-4 [DOI] [PubMed] [Google Scholar]
  • 2.Lawn JE, Blencowe H, Oza S, You D, Lee ACC, Waiswa P, et al. Every newborn: progress, priorities, and potential beyond survival. Lancet. 2014;384(9938):189–205. 10.1016/S0140-6736(14)60496-7 [DOI] [PubMed] [Google Scholar]
  • 3.Liu L, Oza S, Hogan D, Perin J, Rudan I, Lawn JE, et al. Global, regional, and national causes of child mortality in 2000–13, with projections to inform post-2015 priorities: an updated systematic analysis. Lancet. 2015;385(9966):430–40. 10.1016/S0140-6736(14)61698-6 [DOI] [PubMed] [Google Scholar]
  • 4.Ganatra HA, Stoll BJ, Zaidi AK. International perspective on early-onset neonatal sepsis. Clin Perinatol. 2010;37(2):501–23. 10.1016/j.clp.2010.02.004 [DOI] [PubMed] [Google Scholar]
  • 5.Alliance for Maternal and Newborn Health Improvement (AMANHI) mortality study group. Population-based rates, timing, and causes of maternal deaths, stillbirths, and neonatal deaths in south Asia and sub-Saharan Africa: a multi-country prospective cohort study. Lancet Glob Health. 2018;6(12):e1297–308. 10.1016/S2214-109X(18)30385-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Technical Working Group on Essential Newborn Care. Essential newborn care. Geneva: World Health Organization; 1994. [cited 2021 Apr 26]. Available from: https://apps.who.int/iris/handle/10665/63076. [Google Scholar]
  • 7.Aleman A, Tomasso G, Cafferata ML, Colomar M, Betran AP. Supply kits for antenatal and childbirth care: a systematic review. Reprod Health. 2017;14(1):175. 10.1186/s12978-017-0436-9 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Garner P, Lai D, Baea M, Edwards K, Heywood P. Avoiding neonatal death: an intervention study of umbilical cord care. J Trop Pediatr. 1994;40(1):24–8. 10.1093/tropej/40.1.24 [DOI] [PubMed] [Google Scholar]
  • 9.Raza SA, Avan BI. Disposable clean delivery kits and prevention of neonatal tetanus in the presence of skilled birth attendants. Int J Gynaecol Obstet. 2013;120(2):148–51. 10.1016/j.ijgo.2012.07.030 [DOI] [PubMed] [Google Scholar]
  • 10.Balsara ZP, Hussein MH, Winch PJ, Gipson R, Santosham M, Darmstadt GL. Impact of clean delivery kit use on clean delivery practices in Beni Suef governorate, Egypt. J Perinatol. 2009;29(10):673–9. 10.1038/jp.2009.80 [DOI] [PubMed] [Google Scholar]
  • 11.Jokhio AH, Winter HR, Cheng KK. An intervention involving traditional birth attendants and perinatal and maternal mortality in Pakistan. N Engl J Med. 2005;352(20):2091–9. 10.1056/NEJMsa042830 [DOI] [PubMed] [Google Scholar]
  • 12.Seward N, Osrin D, Li L, Costello A, Pulkki-Brannstrom AM, Houweling TAJ, et al. Association between clean delivery kit use, clean delivery practices, and neonatal survival: pooled analysis of data from three sites in South Asia. PLoS Med. 2012;9(2):e1001180. 10.1371/journal.pmed.1001180 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Darmstadt GL, Hassan M, Balsara ZP, Winch PJ, Gipson R, Santosham M. Impact of clean delivery-kit use on newborn umbilical cord and maternal puerperal infections in Egypt. J Health Popul Nutr. 2009;27(6):746–54. 10.3329/jhpn.v27i6.4326 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Semrau KEA, Herlihy J, Grogan C, Musokotwane K, Yeboah-Antwi K, Mbewe R, et al. Effectiveness of 4% chlorhexidine umbilical cord care on neonatal mortality in Southern Province, Zambia (ZamCAT): a cluster-randomised controlled trial. Lancet Glob Health. 2016;4(11):e827–36. 10.1016/S2214-109X(16)30215-7 [DOI] [PubMed] [Google Scholar]
  • 15.Hamer DH, Herlihy JM, Musokotwane K, Banda B, Mpamba C, Mwangelwa B, et al. Engagement of the community, traditional leaders, and public health system in the design and implementation of a large community-based, cluster-randomized trial of umbilical cord care in Zambia. Am J Trop Med Hyg. 2015;92(3):666–72. 10.4269/ajtmh.14-0218 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Central Statistical Office, Ministry of Health, Tropical Diseases Research Centre, University of Zambia. Zambia demographic and health survey 2007. Calverton (MD): Macro International; 2009. [Google Scholar]
  • 17.World Health Organization. Managing possible serious bacterial infection in young infants when referral is not feasible. Geneva: World Health Organization; 2015. [cited 2021 Apr 27]. Available from: https://www.who.int/maternal_child_adolescent/documents/bacterial-infection-infants/en/. [PubMed] [Google Scholar]
  • 18.World Health Organization. Preterm birth. Geneva: World Health Organization; 2018. [cited 2021 Apr 27]. Available from: https://www.who.int/news-room/fact-sheets/detail/preterm-birth. [Google Scholar]
  • 19.World Health Organization. International statistical classification of diseases and related health problems (ICD). ICD-11. Geneva: World Health Organization; 2021. [cited 2021 Apr 27]. Available from: https://www.who.int/classifications/icd/en/. [Google Scholar]
  • 20.Oza S, Lawn JE, Hogan DR, Mathers C, Cousens SN. Neonatal cause-of-death estimates for the early and late neonatal periods for 194 countries: 2000–2013. Bull World Health Organ. 2015;93(1):19–28. 10.2471/BLT.14.139790 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Republic of Zambia Ministry of Health. Reproductive, maternal, newborn, child and adolescent health and nutrition communication and advocacy strategy 2018–2021. Lusaka: Republic of Zambia Ministry of Health; 2019. [cited 2020 Jun 16]. Available from: https://www.moh.gov.zm/?wpfb_dl=111. [Google Scholar]
  • 22.Owens L, Semrau K, Mbewe R, Musokotwane K, Grogan C, Maine D, et al. The state of routine and emergency obstetric and neonatal care in Southern Province, Zambia. Int J Gynaecol Obstet. 2015;128(1):53–7. 10.1016/j.ijgo.2014.07.028 [DOI] [PubMed] [Google Scholar]
  • 23.Bhutta ZA, Das JK, Bahl R, Lawn JE, Salam RA, Paul VK, et al. Can available interventions end preventable deaths in mothers, newborn babies, and stillbirths, and at what cost? Lancet. 2014;384(9940):347–70. 10.1016/S0140-6736(14)60792-3 [DOI] [PubMed] [Google Scholar]
  • 24.Winani S, Wood S, Coffey P, Chirwa T, Mosha F, Changalucha J. Use of a clean delivery kit and factors associated with cord infection and puerperal sepsis in Mwanza, Tanzania. J Midwifery Womens Health. 2007;52(1):37–43. 10.1016/j.jmwh.2006.09.004 [DOI] [PubMed] [Google Scholar]
  • 25.Hundley VA, Avan BI, Braunholtz D, Graham WJ. Are birth kits a good idea? A systematic review of the evidence. Midwifery. 2012;28(2):204–15. 10.1016/j.midw.2011.03.004 [DOI] [PubMed] [Google Scholar]
  • 26.Pell LG, Turab A, Bassani DG, Shi J, Soofi S, Hussain M, et al. Effect of an integrated neonatal care kit on neonatal health outcomes: a cluster randomised controlled trial in rural Pakistan. BMJ Glob Health. 2019;4(3):e001393. 10.1136/bmjgh-2019-001393 [DOI] [PMC free article] [PubMed] [Google Scholar]

Decision Letter 0

Artur Arikainen

15 Dec 2020

Dear Dr Park,

Thank you for submitting your manuscript entitled "Differential effects of components of clean delivery kits on newborn mortality: results from the Zambia Chlorhexidine Application Trial (ZamCAT)" for consideration by PLOS Medicine.

Your manuscript has now been evaluated by the PLOS Medicine editorial staff and I am writing to let you know that we would like to send your submission out for external peer review.

However, before we can send your manuscript to reviewers, we need you to complete your submission by providing the metadata that is required for full assessment. To this end, please login to Editorial Manager where you will find the paper in the 'Submissions Needing Revisions' folder on your homepage. Please click 'Revise Submission' from the Action Links and complete all additional questions in the submission questionnaire.

Please re-submit your manuscript within two working days, i.e. by .

Login to Editorial Manager here: https://www.editorialmanager.com/pmedicine

Once your full submission is complete, your paper will undergo a series of checks in preparation for peer review. Once your manuscript has passed all checks it will be sent out for review.

Feel free to email us at plosmedicine@plos.org if you have any queries relating to your submission.

Kind regards,

Artur A. Arikainen,

Associate Editor

PLOS Medicine

Decision Letter 1

Emma Veitch

30 Jan 2021

Dear Dr. Park,

Thank you very much for submitting your manuscript "Differential effects of components of clean delivery kits on newborn mortality: results from the Zambia Chlorhexidine Application Trial (ZamCAT)" (PMEDICINE-D-20-05939R1) for consideration at PLOS Medicine.

Your paper was evaluated by a senior editor and discussed among all the editors here. It was also sent to three independent reviewers, including a statistical reviewer (r#2). The reviews are appended at the bottom of this email and any accompanying reviewer attachments can be seen via the link below:

[LINK]

In light of these reviews, I am afraid that we will not be able to accept the manuscript for publication in the journal in its current form, but we would like to consider a revised version that addresses the reviewers' and editors' comments. Obviously we cannot make any decision about publication until we have seen the revised manuscript and your response, and we plan to seek re-review by one or more of the reviewers.

In revising the manuscript for further consideration, your revisions should address the specific points made by each reviewer and the editors. Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments, the changes you have made in the manuscript, and include either an excerpt of the revised text or the location (eg: page and line number) where each change can be found. Please submit a clean version of the paper as the main article file; a version with changes marked should be uploaded as a marked up manuscript.

In addition, we request that you upload any figures associated with your paper as individual TIF or EPS files with 300dpi resolution at resubmission; please read our figure guidelines for more information on our requirements: http://journals.plos.org/plosmedicine/s/figures. While revising your submission, please upload your figure files to the 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. 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 us at PLOSMedicine@plos.org.

We expect to receive your revised manuscript by Feb 22 2021 11:59PM. Please email us (plosmedicine@plos.org) if you have any questions or concerns.

***Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.***

We ask every co-author listed on the manuscript to fill in a contributing author statement, making sure to declare all competing interests. If any of the co-authors have not filled in the statement, we will remind them to do so when the paper is revised. If all statements are not completed in a timely fashion this could hold up the re-review process. If new competing interests are declared later in the revision process, this may also hold up the submission. Should there be a problem getting one of your co-authors to fill in a statement we will be in contact. YOU MUST NOT ADD OR REMOVE AUTHORS UNLESS YOU HAVE ALERTED THE EDITOR HANDLING THE MANUSCRIPT TO THE CHANGE AND THEY SPECIFICALLY HAVE AGREED TO IT. You can see our competing interests policy here: http://journals.plos.org/plosmedicine/s/competing-interests.

Please use the following link to submit the revised manuscript:

https://www.editorialmanager.com/pmedicine/

Your article can be found in the "Submissions Needing Revision" folder.

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see http://journals.plos.org/plosmedicine/s/submission-guidelines#loc-methods.

Please ensure that the paper adheres to the PLOS Data Availability Policy (see http://journals.plos.org/plosmedicine/s/data-availability), which requires that all data underlying the study's findings be provided in a repository or as Supporting Information. For data residing with a third party, authors are required to provide instructions with contact information for obtaining the data. PLOS journals do not allow statements supported by "data not shown" or "unpublished results." For such statements, authors must provide supporting data or cite public sources that include it.

We look forward to receiving your revised manuscript.

Sincerely,

Emma Veitch, PhD

PLOS Medicine

On behalf of Artur Arikainen, PhD, Associate Editor,

PLOS Medicine

plosmedicine.org

-----------------------------------------------------------

Requests from the editors:

*Please structure your abstract using the PLOS Medicine headings (Background, Methods and Findings, Conclusions -- "Methods and Findings" is a single subsection).

*It might be appropriate to add to the abstract (briefly) the context that although conducted within a randomized trial, the randomization was ignored for the purposes of this analysis, with the participants' data pooled across arms (assuming that is correct) - essentially converting it into something akin to a prospective cohort analysis. That could also be spelt out more clearly upfront in the Methods section, potentially.

*In the last sentence of the Abstract Methods and Findings section, please include a note about any key limitations of the study's methodology - perhaps one of the most obvious relates to the above point, also brought out by reviewers noting that causality cannot be firmly established due to the potential for confounding (which could be expanded on in the main Discussion, as noted by one reviewer, in terms of the potential source(s) and direction of this).

*Please add the trial registration details to the end of the abstract as per in this (published) example - https://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.1002775

*At this stage, we ask that you include a short, non-technical Author Summary of your research to make findings accessible to a wide audience that includes both scientists and non-scientists. The Author Summary should immediately follow the Abstract in your revised manuscript. This text is subject to editorial change and should be distinct from the scientific abstract. Please see our author guidelines for more information: https://journals.plos.org/plosmedicine/s/revising-your-manuscript#loc-author-summary

*Regarding the point above, and raised by reviewer(s), currently the Discussion section notes - "In summary, this analysis demonstrated the impact of CDKs on reducing newborn mortality..." - and it might be appropriate to reword this, particularly use of "impact".

*Please complete the CONSORT checklist (https://www.equator-network.org/reporting-guidelines/consort/) and include a copy of the completed checklist as supporting material with the revised paper. Ideally please ensure that all relevant parts of CONSORT are described in the revised paper, although some elements will only be relevant (and can be found) in the original trial publication.

*Please clarify if the analysis reported here corresponds to one laid out in a prospective protocol or analysis plan. Please state this (either way) early in the Methods section.

a) If a prospective analysis plan (from your funding proposal, IRB or other ethics committee submission, study protocol, or other planning document written before analyzing the data) was used in designing the study, please include the relevant prospectively written document with your revised manuscript as a Supporting Information file to be published alongside your study, and cite it in the Methods section. A legend for this file should be included at the end of your manuscript.

b) If no such document exists, please make sure that the Methods section transparently describes when analyses were planned, and when/why any data-driven changes to analyses took place.

c) In either case, changes in the analysis-- including those made in response to peer review comments-- should be identified as such in the Methods section of the paper, with rationale.

-----------------------------------------------------------

Comments from the reviewers:

Reviewer #1:

General comments

Clean delivery kits may reduce death from neonatal infections so this study assessed the potential associations of use of components of the clean delivery kits with newborn mortality in a large cluster RCT.

This study assesses associations so causality should not be inferred. The title implies causality, which should be corrected.

Perinatal mortality would be a good measure but stillbirths are not reported.

Abstract

The abstract should address that the assessment of the use of the components of the CDK by the mothers and was done late. This should caution the interpretation of the results.

Introduction

The rationale is well-justified.

The final sentence should not imply causality.

Methods

The data on use of the components of the clean delivery kits (CDK) was obtained from the mothers four days after delivery. It is unfortunate these data were not collected at delivery because recall bias can severely affect the results. The mothers may not be able to recall details of the use of the CDK. These data were collected after day 1 mortality and most of the first week mortality were known. This can also lead to major biases.

Non-users of specific CDK component was too low to analyze statistically. This is an important limitation which combined with the recall bias and data collection after most of the first week deaths limits the confidence in the results.

Stillbirth data are needed as stillbirths could be due to infection and because the distinction between stillbirth and death in the first minutes is difficult to assess. It is essential to report the combined stillbirth data with the day 1 mortality data as well as the stillbirth/first week mortality data (perinatal death) which is ideal for reporting when assessing intrapartum and birth interventions.

Results

Infection in an important cause of late neonatal mortality but individual component of CDK use had not significant association with late newborn deaths. Data on use of components of the CDK were collected on day 4 so it is possible that recall bias had nothing to do with late deaths and thus no association. Furthermore, multivariate logistic regression did not show any significant associations between signs of newborn infection at days 1, 4, 10, or 28 and CDK components or any of the covariates. This raises major concerns about the purported association of components of the CDK and neonatal mortality.

It is not reported whether the deaths in the first week disproportionately caused by infections. Data on verbal autopsy and causes of death were collected but not reported.

Discussion

The Discussion should address the results as potential associations rather than imply causality which is implied multiple times in the Discussion. Terms such as impact, effect, and benefit should not be used in the interpretation of the results.

-----------------------------------------------------------

Reviewer #2:

Thanks for the opportunity to review your manuscript. My role is as a statistical reviewer so my comments and queries focus on the study design, data, and analysis.

This study presents secondary analyses from a large cRCT aiming to reduce neonatal mortality in Zambia. These include comparing neonatal mortality rates according to use of specific components of a clean delivery kit, maternal and neonatal characteristics. There are some very strong differences in rates of NMR with some of the kit components.

I have put general queries first, followed by questions specific to a particular part of the manuscript (with a page and line reference).

Some of the language about the association between the CDK components and NMR strays into causation e.g. "showed reduction in risk" (L217), there are few other instances of this. These should be rephrased as although these relationships are strong and seem reasonable there is still the possibility of confounding with an unmeasured variable.

I would also try not to use 'significant' or 'statistically significant', rather focus on the effect estimates and use the p-values to as a demonstration of evidence. The effect sizes are very impressive so it would be a shame not to highlight these.

P6. L164. To confirm, the main study used GEEs as there was cluster randomisation, the randomisation status wasn't used in any of these analyses so a standard logistic regression model was used throughout?

P6, L167. 'Confounding by indication' has become a fairly vague term with different interpretations in different sub-fields of health and medicine. It would be more useful to be specific about how you think the confounding would affect your analysis here (keeping in mind PLOS Med has a general audience).

P6, L174. Theoretically there are 2**7 = 128 permutations of use of the 7 different components of the CDK. How were the 'key permutations' decided? It isn't clear what the 'analysis of interactions' was - is this the interaction with the other patient and cluster level characteristics?

P6, L175. Were the risk factors for newborn sepsis that were included as adjustments used in the same form as presented in table 1?

P6, L180. Was an analysis plan developed for this secondary analysis?

P6, L189. The missing data strategy (complete-case analysis) should be detailed in the methods. It would also be helpful to see basic summary information that compares participants included vs. excluded on key characteristics (e.g. what is presented in Table 1). I don't think that a complete-case excluding ~2.5% of the original participants is likely to be a problem, but it would be reassuring to see there were no strong differences.

P9, L238. Was the interaction between delivery location and CDK etc. formally tested with an interaction?

-----------------------------------------------------------

Reviewer #3:

While this study is a secondary analysis that employs data from the primary Zambia chlorhexidine Application Trial, the findings are nonetheless compelling.

Almost 37,000 newborns were included in the analyses which reported on independent rates of the "6 cleans" based upon the provision of clean delivery kits. Independent rates of reduction in mortality for each component contained in the kit have been reported, along with its association on immediate newborn death, early as well as late neonatal mortality.

It appears evident from data provided in this paper, utilizing logistic regression analyses, that employment of clean birthing practices has the potential to produce significant reductions in mortality. The impact appears to be meaningful immediately after birth and within 7 days of delivery with no additional reduction in mortality after that time.

The authors appropriately point out the weaknesses inherent in using self-reported data. It would be interesting to determine why cord clamping was not practiced and home births relative to its use at facilities. Suggestions for education and training of community health providers may be important in addressing this difference in future interventions.

The paper would be enhanced by including costs associated with providing the intervention.

Overall, however, there is sufficiently strong evidence presented to expand the use of clean delivery kits as an important component for reducing immediate and early neonatal mortality in Zambia and likely in other sub-Saharan communities.

-----------------------------------------------------------

Any attachments provided with reviews can be seen via the following link:

[LINK]

Decision Letter 2

Richard Turner

24 Mar 2021

Dear Dr. Park,

Thank you very much for re-submitting your manuscript "Association between components of clean delivery kits and newborn mortality: results from the Zambia Chlorhexidine Application Trial (ZamCAT)" (PMEDICINE-D-20-05939R2) for consideration at PLOS Medicine.

I have discussed the paper with editorial colleagues and our academic editor, and it was also seen again by one reviewer. I am pleased to tell you that, provided the remaining editorial and production issues are dealt with, we expect to be able to accept the paper for publication in the journal.

The remaining issues that need to be addressed are listed at the end of this email. Any accompanying reviewer attachments can be seen via the link below. Please take these into account before resubmitting your manuscript:

[LINK]

***Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.***

In revising the manuscript for further consideration here, please ensure you address the specific points made by each reviewer and the editors. In your rebuttal letter you should indicate your response to the reviewers' and editors' comments and the changes you have made in the manuscript. Please submit a clean version of the paper as the main article file. A version with changes marked must also be uploaded as a marked up manuscript file.

Please also check the guidelines for revised papers at http://journals.plos.org/plosmedicine/s/revising-your-manuscript for any that apply to your paper. If you haven't already, we ask that you provide a short, non-technical Author Summary of your research to make findings accessible to a wide audience that includes both scientists and non-scientists. The Author Summary should immediately follow the Abstract in your revised manuscript. This text is subject to editorial change and should be distinct from the scientific abstract.

We hope to receive your revised manuscript within 1 week. Please email us (plosmedicine@plos.org) if you have any questions or concerns.

We ask every co-author listed on the manuscript to fill in a contributing author statement. If any of the co-authors have not filled in the statement, we will remind them to do so when the paper is revised. If all statements are not completed in a timely fashion this could hold up the re-review process. Should there be a problem getting one of your co-authors to fill in a statement we will be in contact. YOU MUST NOT ADD OR REMOVE AUTHORS UNLESS YOU HAVE ALERTED THE EDITOR HANDLING THE MANUSCRIPT TO THE CHANGE AND THEY SPECIFICALLY HAVE AGREED TO IT.

Please ensure that the paper adheres to the PLOS Data Availability Policy (see http://journals.plos.org/plosmedicine/s/data-availability), which requires that all data underlying the study's findings be provided in a repository or as Supporting Information. For data residing with a third party, authors are required to provide instructions with contact information for obtaining the data. PLOS journals do not allow statements supported by "data not shown" or "unpublished results." For such statements, authors must provide supporting data or cite public sources that include it.

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text, or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript.

Please note, when your manuscript is accepted, an uncorrected proof of your manuscript will be published online ahead of the final version, unless you've already opted out via the online submission form. If, for any reason, you do not want an earlier version of your manuscript published online or are unsure if you have already indicated as such, please let the journal staff know immediately at plosmedicine@plos.org.

Please let me know if you have any questions, and we look forward to receiving the revised manuscript shortly.   

Sincerely,

Richard Turner, PhD

Senior Editor, PLOS Medicine

rturner@plos.org

------------------------------------------------------------

Requests from Editors:

Please finalize the arrangements for data deposition in a publicly-accessible repository.

So as to comply with journal style, please adapt the title to "Components of clean delivery kits and newborn mortality in the Zambia Chlorhexidine Application Trial (ZamCAT): an observational study" or similar.

Please quote the study dates in the abstract.

At lines 44-49, please adapt "reduced newborn mortality" to "lower risk of newborn mortality", for example.

Please add a new final sentence to the "Methods and findings" subsection of your abstract, which should begin "Study limitations include ..." or similar and quote 2-3 of the study's main limitations.

Please use the active voice for one or two points in your Author summary (e.g., "We analysed data ...").

Please state explicitly in your Methods section that the analysis did not have a protocol or prespecified analysis plan (assuming this is the case); are you able to state that there were no data-driven changes in the analysis plan?

Please avoid language implying causality throughout the text. For example, at line 400 rather than "were associated with the greatest reduction ..." please adapt the text to "were associated with the lowest risk of ..." or similar.

Please use the following style throughout the text, except where a number is used to start a sentence: "All 7 components ...".

Please remove the information on study funding from the Acknowledgements section at the end of the main text. This information should appear only in the article metadata, via entries in the submission form.

Please adapt the attached CONSORT checklist so that individual items are referred to by section (e.g., "Methods") and paragraph number rather than by page or line numbers, as the latter generally change in the event of publication.

Please rename the file "S1_CONSORT_Checklist" or similar and refer to it in your Methods section by this label.

Comments from Reviewers:

*** Reviewer #2:

Thanks for the revised manuscript and replies to my original queries. This is an interesting and useful manuscript and overall I recommend it. There are a few minor changes I recommend.

The language around causality is improved. In L401 I think 'connection' is still too strong, 'association' would be more accurate.

For the most common combinations, I would add change the table description from 'top' to 'most frequent' as this is more specific and not every reader will be examining the methods as closely as I like to.

Women excluded from the analysis for missing data are broadly the same as those included - there are more older women, and more likely to deliver in a hospital, but I don't see this as being problematic with 1583 missing from the original sample.

L297. 'Multivariable' is a more suitable description with one outcome and several covariates.

L308. Is the adjusted analysis shown somewhere? If in an appendix (I couldn't find it) please refer to this. This should be included somewhere, either by expanding Tab 4 or including in an appendix.

Supplemental Table 1 didn't appear in the document when I downloaded it.

***

Any attachments provided with reviews can be seen via the following link:

[LINK]

Decision Letter 3

Richard Turner

3 Apr 2021

Dear Dr Park, 

On behalf of my colleagues and the Academic Editor, Dr Myers, I am pleased to inform you that we have agreed to publish your manuscript "Components of clean delivery kits and newborn mortality in the Zambia Chlorhexidine Application Trial (ZamCAT): an observational study" (PMEDICINE-D-20-05939R3) in PLOS Medicine.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow up email. Please be aware that it may take several days for you to receive this email; during this time no action is required by you. Once you have received these formatting requests, please note that your manuscript will not be scheduled for publication until you have made the required changes.

Prior to final acceptance, please remove the grant number from the acknowledgements section (this also appears in the article metadata).

Please also add details of the page providing access to study data (in article metadata).

In the meantime, please log into Editorial Manager at http://www.editorialmanager.com/pmedicine/, click the "Update My Information" link at the top of the page, and update your user information to ensure an efficient production process. 

PRESS

We frequently collaborate with press offices. If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximise its impact. If the press office is planning to promote your findings, we would be grateful if they could coordinate with medicinepress@plos.org. If you have not yet opted out of the early version process, we ask that you notify us immediately of any press plans so that we may do so on your behalf.

We also ask that you take this opportunity to read our Embargo Policy regarding the discussion, promotion and media coverage of work that is yet to be published by PLOS. As your manuscript is not yet published, it is bound by the conditions of our Embargo Policy. Please be aware that this policy is in place both to ensure that any press coverage of your article is fully substantiated and to provide a direct link between such coverage and the published work. For full details of our Embargo Policy, please visit http://www.plos.org/about/media-inquiries/embargo-policy/.

To enhance the reproducibility of your results, we recommend that you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. Additionally, PLOS ONE offers an option to publish peer-reviewed clinical study protocols. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols

Thank you again for submitting to PLOS Medicine. We look forward to publishing your paper. 

Sincerely, 

Richard Turner, PhD 

Senior Editor, PLOS Medicine

rturner@plos.org

Associated Data

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

    Supplementary Materials

    S1 CONSORT Checklist

    (DOC)

    S1 Table. Clean delivery kit (CDK) use by component and perinatal mortality rate.

    (DOCX)

    S2 Table. Adjusted logistic regression—association between clean delivery kit (CDK) components and perinatal mortality stratified by delivery location.

    (DOCX)

    S3 Table. Adjusted association between timing of newborn death and the use of clean delivery kit (CDK) components—with covariates.

    (DOCX)

    Attachment

    Submitted filename: Ver 2.2 Response to Reviewers.docx

    Attachment

    Submitted filename: Ver 3.2 Response to reviewers.docx

    Data Availability Statement

    The data is available at Boston University's data repository: https://open.bu.edu/handle/2144/42348.


    Articles from PLoS Medicine are provided here courtesy of PLOS

    RESOURCES