Abstract
Background:
The Government of India initiated different programs to reduce neonatal mortality. However, the variability of neonatal deaths occurs among states of India.
Objective:
This study aimed to identify the differential determinants associated with neonatal deaths in northern and southern regions of India.
Materials and Methods:
Bivariate analysis and Cox regression analysis have been performed to evaluate the predictors of neonatal mortality from National Family Health Survey (NFHS-4) data.
Results:
For neonatal mortality, mother and child factors became more consistent in the southern region than northern regions of the country, while household factor was almost the same in both regions of India.
Conclusions:
Primary intervention is also required to reduce public health problem as neonatal mortality. It should be focused on education of mother, birth interval, age at birth, antenatal care, poverty reduction programs, and proper heath facility to pregnant mothers.
Keywords: Cox regression, India, neonatal mortality, northern regions, southern regions
INTRODUCTION
In the world approximately 130 million infants born annually and more than 4 million infants die within first 28 days of life[1] and most of deaths occur in low and middle income countries.[2] Last 30 years, the diminution in neonatal mortality rates had been found slower as compared to under-five and child mortality rates.[3,4] A study indicates that community education has a significant positive effect on child mortality in northeastern India. The study unfolds that community education effect is more than maternal factors on child mortality.[5] Socioeconomic factors such as place of residence, woman's education, and economic condition are known as full power determinants of infant and child mortality.[6] It has investigated the positive effect of mother's education on child survival.[7] Gender disparity in health and education is higher in South Asian countries than anywhere else in the world. The various differentials and determinants of neonatal and infant mortality rates were estimated in rural southern states of India. The trend and pattern were also found which are based on household survey data.[8] The under-five and neonatal mortality rates of different districts of India were analyzed to explore the district-level variability in neonatal and under-five mortality with the reference of Sustainable Development Goal 3 and National Family Health Survey (NFHS-4).[9] A study has been done to identify the cause of under-five mortality at national, regional, and state levels in India.[10]
It has found spatial contours where poverty, infant, under-five mortality, and child malnutrition are clustered. The factor of geographical regions influences child nutrition and infant and under-five mortality in India.[11]
In India, around one million babies die every year before completing their 1st month of life, contributing to one-fourth of the global burden. South–North differences in neonatal mortality exist with the mortality rate higher in North as compared to South India from NFHS-4.[12] The frequent causes of neonatal deaths in India include infections, birth asphyxia, and prematurity. Henceforth, the present study aims to explore the specific factors that affect neonatal mortality in northern and southern states of India.
MATERIALS AND METHODS
The study used the data of NFHS-4, which is available in public domain and based on national representative sample of 699,686 women aged 15–49 years and 112,122 men aged 15–54 years from all 36 states. A principal objective of the survey has been to provide information about the estimates of fertility family planning, reproductive and child health, infant and child mortality, nutrition of women and children, the quality of health and family welfare services, and socioeconomic conditions. The northern and southern states of India were divided geographically. Moreover, the states of southern part (Andhra Pradesh, Telangana, Karnataka, Kerala, and Tamil Nadu) and northern states (Delhi, Haryana, Himachal Pradesh, Jammu Kashmir, Punjab, Uttar Pradesh, and Uttarakhand) are included in the study in Figure 1. Bivariate analysis has been applied to check the association of the covariates. Cox regression analysis is used to obtain the risk of an infant dying before completing 4 weeks of their life. The dependent variable in the model is neonatal death in neonatal period in Figure 2.
Figure 1.
Prevalence of neonatal mortality rate in northern and southern states of India
Figure 2.
Factors associated with neonatal mortality
RESULTS
Prevalence of neonatal mortality in southern and northern regions of India
Mother factors
Mother factors include mother education, occupation, institutional delivery, and age at first birth. In North India, illiterate women experience more neonatal deaths. The neonatal mortality is higher among noninstitutional delivery as compared to institutional delivery. Mother age at first birth after 20 years was less likely to have neonatal mortality than before 20 years in northern states. In general, southern states of India had less neonatal mortality among all the background characteristics except occupation one [Table 1].
Table 1.
Differential determinants of neonatal mortality (per 1000 live birth) by mother, child, and household factors in southern and northern regions of India (2015-2016)
| Background characteristics | Southern regions (n=752) | Northern regions (n=2394) |
|---|---|---|
|
| ||
| n (%) | n (%) | |
| Mother factors | ||
| Education | ||
| Not educated | 180 (31.4)* | 1041 (44.9)* |
| Educated | 572 (14.7) | 1352 (34.2) |
| Occupation | ||
| Not working | 711 (16.6) | 2330 (38.2) |
| Working | 41 (21.0) | 64 (36.9) |
| Institutional delivery | ||
| Not institutional | 64 (31.8)* | 751 (43.3)* |
| Institutional | 688 (16.1) | 1642 (36.2) |
| Age at first birth (years) | ||
| <20 | 325 (16.5) | 1198 (43.0)* |
| >20 | 427 (17.1) | 1195 (34.3) |
| Child factors | ||
| Birth interval (years)@ | ||
| <2 | 139 (18.2) | 700 (52.2)* |
| >2 | 245 (15.2) | 799 (28.6) |
| Birth size | ||
| Average and larger | 495 (12.3)* | 1748 (33.0)* |
| Small and very small | 222 (51.6) | 641 (66.2) |
| Child sex | ||
| Male | 447 (19.3)* | 1359 (41.0)* |
| Female | 305 (14.2) | 1035 (35.0) |
| Currently breastfeeding | ||
| No | 517 (23.8)* | 1549 (66.7)* |
| Yes | 235 (10.2) | 845 (21.4) |
| Household factors | ||
| Wealth index | ||
| Poor | 244 (27.1)* | 1323 (47.6)* |
| Middle | 274 (21.5) | 484 (42.4) |
| Rich | 234 (10.2) | 587 (24.9) |
| Type of residence | ||
| Urban | 200 (10.7)* | 490 (28.6)* |
| Rural | 552 (21.2) | 1903 (41.7) |
| Toilet facility | ||
| No facility | 371 (25.1)* | 1241 (47.1)* |
| Facility | 381 (12.8) | 1152 (31.7) |
| Caste | ||
| SC/ST | 289 (22.8)* | 679 (38.2)* |
| OBC | 370 (14.6) | 1236 (41.8) |
| General | 73 (14.9) | 440 (31.9) |
| Religion | ||
| Hindu | 648 (17.9)* | 1861 (39.4)* |
| Muslim and others | 104 (12.3) | 533 (34.2) |
* Significant (p<0.001), @ First births are excluded
Child factors
Neonatal mortality was high in <2 years of birth interval in northern states of India. Neonatal mortality was high in northern India as compared to southern India. When the birth size of the baby was very small, neonatal mortality was high in North India compared to South India. Neonatal mortality was very high among currently nonbreastfed children than breastfed children in both South and North India. Furthermore, high neonatal mortality was observed in male children in both South and North India. Although, birth-interval, birth size, child sex, and breastfeeding were the most important predictors of neonatal mortality in both southern and northern states of India, which was statistically significant at 5% level of significance [Table 1].
Household factors
Neonatal mortality was significantly high among poor- and middle-class families, while this mortality was substantially equal in average economic family in both northern and southern India. There was a vast disparity in neonatal death between rural and urban areas. Results also show high mortality among SC/ST in northern India whereas, in southern India, it was significantly high in other backward classes. Households with toilet facility show less mortality as compared to the households without toilet facility. Neonatal mortality is more in rural and SC/ST families than the counterpart. Respondents belonging to Hindu religion were more mortality than Muslim and other religions [Table 1].
Cox regression analysis for neonatal mortality
Factors associated with mother factors
The results of the Cox regression models revealed that mother's education was highly responsible (hazard ratio [HR] = 0.57 [0.44–0.71], HR = 0.81 [0.74–0.87]) for neonatal mortality in South and North India, respectively. In working women, the risk of neonatal mortality was higher (HR = 1.18 [0.80–1.74], HR = 0.85 [0.67–1.06]) compared to those who were not working in southern and northern states, respectively. The chances of neonatal mortality were more in noninstitutional delivery of mothers as compared to institutional delivery (HR = 1.01 [0.67–1.48], HR = 1.03 [0.94–1.11]) in southern and northern states, respectively. The risk of neonatal mortality was also higher in mothers who were below 20 years of age at first birth as compared to the age of mothers above 20 years (HR = 1.13 [0.92–1.37], HR = 0.89 [0.82–0.96]) in South and North India, respectively [Table 2].
Table 2.
Cox regression analysis for neonatal mortality by mother, child, and household factors in southern and northern regions of India (2015-2016)
| Background characteristics | Southern regions | Northern regions | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Mother factors | Child factors | Household factors | All factors | Mother factors | Child factors | Household factors | All factors | |||||||||
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| Model 1 | Model 2 | Model 3 | Model 4 | Model 1 | Model 2 | Model 3 | Model 4 | |||||||||
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| HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | HR | 95% CI | |
| Mother factors | ||||||||||||||||
| Education | ||||||||||||||||
| Not educated® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Educated | 0.57*** | 0.44-0.71 | 0.92 | 0.63-1.33 | 0.81*** | 0.74-0.87 | 0.85*** | 0.76-0.95 | ||||||||
| Occupation | ||||||||||||||||
| Not working® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Working | 1.18 | 0.80-1.74 | 1.27 | 0.76-2.13 | 0.85 | 0.67-1.06 | 0.85 | 0.65-1.12 | ||||||||
| Institutional delivery | ||||||||||||||||
| Not institutional® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Institutional | 1.01 | 0.67-1.48 | 1.17 | 0.68-2.01 | 1.03 | 0.94-1.11 | 1.18*** | 1.05-1.31 | ||||||||
| Age at first birth (years) | ||||||||||||||||
| <20® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| >20 | 1.13 | 0.92-1.37 | 1.21 | 0.90-1.61 | 0.89*** | 0.82-0.96 | 0.92*** | 0.82-0.94 | ||||||||
| Child factors | ||||||||||||||||
| Birth interval (years) | ||||||||||||||||
| <2® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| >2 | 0.69*** | 0.51-0.91 | 0.76** | 0.56-1.02 | 0.60*** | 0.54-0.66 | 0.61*** | 0.54-0.67 | ||||||||
| Birth size | ||||||||||||||||
| Average and larger® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Small and very small | 4.57*** | 3.38-6.16 | 4.38*** | 3.20-5.98 | 2.30*** | 2.06-2.56 | 2.25*** | 2.01-2.51 | ||||||||
| Child sex | ||||||||||||||||
| Male® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Female | 0.93 | 0.69-1.22 | 0.97 | 0.72-1.29 | 0.91** | 0.82-1.00 | 0.91** | 0.82-1.01 | ||||||||
| Currently breastfeeding | ||||||||||||||||
| No® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Yes | 0.63*** | 0.44-0.89 | 0.60*** | 0.41-0.85 | 0.50*** | 0.44-0.55 | 0.46*** | 0.41-0.51 | ||||||||
| Household factors | ||||||||||||||||
| Wealth index | ||||||||||||||||
| Poor® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Middle | 0.85 | 0.66-1.07 | 0.94 | 0.64-1.36 | 0.90** | 0.80-0.99 | 0.91*** | 0.78-0.95 | ||||||||
| Rich | 0.48*** | 0.35-0.66 | 0.61** | 0.37-0.98 | 0.59*** | 0.52-0.66 | 0.62*** | 0.52-0.73 | ||||||||
| Type of residence | ||||||||||||||||
| Urban® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Rural | 1.09 | 0.85-1.38 | 0.99 | 0.70-1.40 | 1.04 | 0.93-1.16 | 1.01 | 0.87-1.15 | ||||||||
| Toilet facility | ||||||||||||||||
| No facility® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Facility | 0.94 | 0.73-1.19 | 1.01 | 0.69-1.47 | 0.98 | 0.88-1.08 | 0.96 | 0.84-1.09 | ||||||||
| Caste | ||||||||||||||||
| SC/ST® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| OBC | 0.80** | 0.64-0.98 | 0.93 | 0.67-1.27 | 1.09** | 0.99-1.19 | 1.09 | 0.97-1.22 | ||||||||
| General | 0.94 | 0.65-1.35 | 1.07 | 0.62-1.83 | 0.91 | 0.81-1.02 | 0.78*** | 0.70-0.87 | ||||||||
| Religion | ||||||||||||||||
| Hindu® | 1.00 | 1.00 | 1.00 | 1.00 | ||||||||||||
| Muslim and others | 0.88 | 0.65-1.19 | 0.88 | 0.57-1.36 | 1.01 | 0.92-1.10 | 0.96 | 0.85-1.08 | ||||||||
P<0.10; **P<0.05; ***P<0.01; ®Reference category. HR: Hazard ratio, CI: Confidence interval
Factors associated with child factors
The risk of neonatal mortality was lower in children born above 2 years of birth interval (HR = 0.69 [0.51–0.91], HR = 0.60 [0.54–0.66]) in both southern and northern regions of India. Children who were having small or very small birth size (HR = 4.57 [3.38–6.16], HR = 2.30 [2.06–2.56]) were four times and two times higher risk than those having average size of birth in South and North India, respectively. The chances of neonatal mortality were more in male children (HR = 0.93 [0.69–1.22], HR = 0.91 [0.82–1.00]) in southern and northern states, respectively. Nonbreastfed children than breastfed children had more risk of mortality (HR = 0.63 [0.44–0.89], HR = 0.50 [0.44–0.55]) in South and North India, respectively [Table 2].
Factors associated with household factor
The risk of neonatal mortality was less among rich class families (HR = 0.48 [0.35–0.66], HR = 0.59 [0.52–0.66]) in South and North India, respectively. The risk of neonatal mortality was higher in rural areas as compared to urban areas (HR = 1.09 [0.85–1.38], HR = 1.04 [0.93–1.16]) in southern and northern states, respectively. The risk of neonatal mortality was higher among SC/ST and other backward classes (OBC) as compared to general category (HR = 0.80 [0.64–0.98], HR = 1.09 [0.99–1.19]) in southern and northern states, respectively. Households with toilet facility have less risk as compared to the households without toilet facility (HR = 0.94 [0.73–1.19], HR = 0.98 [0.88–1.08]) in southern and northern states, respectively. The risk of neonatal mortality was higher among Hindu religion families (HR = 0.88 [0.65–1.19], 1.01 [0.92–1.10]) as compared to Muslim and other religions in southern and northern states, respectively [Table 2].
DISCUSSION
This is a comparative study between the northern and southern regions of India.
Neonatal mortality is high in the northern region than the southern part of India. The study shows that acute respiratory infections, diarrhea, measles, and malaria are the probable causes of neonatal mortality.[12] Deaths from diarrhea are much less frequent than for children under-five and measles and malaria are extremely rare in neonatal age group.[13] This study has also indicated that mother's age at first birth is significantly associated with neonatal mortality in both North and South India after adjustment of child and household factors. A study has highlighted the findings which indicate that maternal age differentials have a significant association with neonatal mortality or preterm birth and low birth weight after adjustment for socioeconomic status or other control variables.[14]
Average and larger birth size is strongly associated with neonatal mortality after adjustment for mother and household factors. This mortality is just half in the northern region while around 70% less in average and larger birth size of children, i.e., death in small birth size, is higher than the average and larger size in the southern region of India. This finding is supported by other literatures that have identified low birth weight as reliable predictors of neonatal mortality.[2] A study in Bangladesh reported that approximately 75% of neonatal deaths associated with low birth weight were accredited to preterm birth rather than small for gestational age infants.[14,15] The sex of neonates does not have a significant association with odds of dying but has more mortality in male children than females. Although, the results of this study are contradicted by some other studies which indicate that females had lower odds of mortality than males during the 1st month of life.[16] This increased odd may also be due to the large proportion of neonatal deaths happening in the initial week, which is the time when sex differences in neonatal mortality are more pronounced. The biological factors that have been concerned with this increased risk of neonatal deaths in male infants include immunodeficiency increasing the risks of infectious diseases in men, late maturity[17] resulting in a high prevalence of respiratory diseases in males, and congenital malformations of the urogenital system.
Birth interval is significantly high in both northern and southern parts of India, supported by some more studies[18,19,20] which indicate a strong association between short preceding birth interval and risk of neonatal death. Similarly, in this study, a higher birth interval provides lower odds than the lower birth interval. This could be connected to maternal depletion syndrome and resource contention between siblings, in addition to a deficiency of care and attention experienced by high-ranked infants.[19,20]
Some of the existing studies have also shown that maternal occupation outside the home significantly increased the odds of neonatal death. Maternal contribution in the labor force may have harmfully affected the care provided to the newborn. Infrequent breastfeeding practiced by infants born to working mothers has been reported to increase the odds of neonatal death.[21] This study has also indicated that currently breastfed children have significantly less experienced neonatal death in both northern and southern regions of India. This mortality is higher in rural, poor households and the house having no toilet facility. The neonatal mortality is the same among the educated mothers, while it was varied significantly in illiterate women between North and South India. Neonatal mortality is higher among female workers as compared to nonworking women in both North and South India. It might be due to the majority of women worked in the nonformal sector that is unskilled labor. More pronounced neonatal death differential is observed with a higher proportion of mortality when the birth size was very small. Neonatal mortality is the same in <2 years of the birth interval in both North and South India. A higher proportion of neonatal mortality was observed in North India when child factors were taken into account. Wealth index had a negative association with neonatal mortality in both North and South India. Deaths were more concentrated in a rural area in both South and North India. Further, neonatal mortality is lower in households with toilet facility, general caste, and in Hindu women than the counterpart.
CONCLUSION
For neonatal mortality, mother and child factors became more consistent in the southern region than northern regions of the country, while household factor was almost the same in both regions of India. Primary intervention is also required to reduce public health problem neonatal deaths. It should be focused on education of mother, birth interval, age at birth and antenatal care, and poverty reduction programs. It should be reduced delivery complications of pregnant mothers through proper health facility.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
The authors would like to thank the editor in chief Dr. Pradeep Kumar and learned referee for their suggestions to improve the quality of contents of the manuscript.
REFERENCES
- 1.Van Lerberghe. Wim. The World Health Report 2005: Make every mother and child count. World Health Organization; 2005. [DOI] [PubMed] [Google Scholar]
- 2.Lawn JE, Cousens S, Zupan J. Lancet Neonatal Survival Steering Team. 4 Million neonatal deaths: When? Where? Why? Lancet. 2005;365:891–900. doi: 10.1016/S0140-6736(05)71048-5. [DOI] [PubMed] [Google Scholar]
- 3.Moss W, Darmstadt GL, Marsh DR, Black RE, Santosham M. Research priorities for the reduction of perinatal and neonatal morbidity and mortality in developing country communities. J Perinatol. 2002;22:484–95. doi: 10.1038/sj.jp.7210743. [DOI] [PubMed] [Google Scholar]
- 4.Hill K, Choi Y. Neonatal mortality in the developing world. Demogr Res. 2006;14:429–52. [Google Scholar]
- 5.Ladusingh L, Singh CH. Place, community education, gender and child mortality in North-East India. Popul Space Place. 2006;12:65–76. [Google Scholar]
- 6.Rama RG, Ladusingh L, Pritamjit R. Nutritional status of children in north-east India. Asia Pac Popul J. 2005;19:39–56. [Google Scholar]
- 7.Mahumud RA, Gow J, Sarker AR, Sultana M, Hossain G, Alam K. Distribution of wealth-stratified inequalities on maternal and child health parameters and influences of maternal-related factors on improvements in child health survival rate in Bangladesh. J Child Health Care. 2021;25:93–109. doi: 10.1177/1367493520909665. [DOI] [PubMed] [Google Scholar]
- 8.Hallad JS, Golandaj JA, Pundappanavar BI, Kar A, Ramesh BM. Trend, differentials and determinants of neonatal and infant mortality in rural North Karnataka. Demogr India. 2018;47:53–66. [Google Scholar]
- 9.Bora JK, Saikia N. Neonatal and under-five mortality rate in Indian districts with reference to Sustainable Development Goal 3: An analysis of the National Family Health Survey of India (NFHS), 2015-2016. PLoS One. 2018;13:e0201125. doi: 10.1371/journal.pone.0201125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Liu L, Chu Y, Oza S, Hogan D, Perin J, Bassani DG, et al. National, regional, and state-level all-cause and cause-specific under-5 mortality in India in 2000-15: A systematic analysis with implications for the Sustainable Development Goals. Lancet Glob Health. 2019;7:e721–34. doi: 10.1016/S2214-109X(19)30080-4. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Singh A, Pathak PK, Chauhan RK, Pan W. Infant and child mortality in India in the last two decades: A geospatial analysis. PLoS One. 2011;6:e26856. doi: 10.1371/journal.pone.0026856. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.International Institute for Population Sciences (IIPS) and ICF. "National family health survey (NFHS-4), 2015-16: India.". Int. Inst. Popul. Sci. ICF. 2017:1–192. [Google Scholar]
- 13.Mengesha HG, Sahle BW. Cause of neonatal deaths in Northern Ethiopia: A prospective cohort study. BMC Public Health. 2017;17:62. doi: 10.1186/s12889-016-3979-8. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Yasmin S, Osrin D, Paul E, Costello A. Neonatal mortality of low-birth-weight infants in Bangladesh. Bull World Health Organ. 2001;79:608–14. [PMC free article] [PubMed] [Google Scholar]
- 15.Al Kibria GM, Khanam R, Mitra DK, Mahmud A, Begum N, Moin SMI, et al. Rates and determinants of neonatal mortality in two rural sub-districts of Sylhet, Bangladesh. PLoS One. 2018;13:e0206795. doi: 10.1371/journal.pone.0206795. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16.Ezeh OK, Agho KE, Dibley MJ, Hall J, Page AN. Determinants of neonatal mortality in Nigeria: Evidence from the 2008 demographic and health survey. BMC Public Health. 2014;14:521. doi: 10.1186/1471-2458-14-521. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17.Alonso V, Fuster V, Luna F. Causes of neonatal mortality in Spain (1975-98): Influence of sex, rural-urban residence and age at death. J Biosoc Sci. 2006;38:537–51. doi: 10.1017/S0021932005026957. [DOI] [PubMed] [Google Scholar]
- 18.Reid A. Neonatal mortality and stillbirths in early twentieth century Derbyshire, England. Popul Stud (Camb) 2001;55:213–32. doi: 10.1080/00324720127696. [DOI] [PubMed] [Google Scholar]
- 19.Rutstein SO. Effects of preceding birth intervals on neonatal, infant and under-five years mortality and nutritional status in developing countries: Evidence from the demographic and health surveys. Int J Gynaecol Obstet. 2005;89(Suppl 1):S7–24. doi: 10.1016/j.ijgo.2004.11.012. [DOI] [PubMed] [Google Scholar]
- 20.Arokiasamy P, Gautam A. Neonatal mortality in the empowered action group states of India: Trends and determinants. J Biosoc Sci. 2008;40:183–201. doi: 10.1017/S0021932007002623. [DOI] [PubMed] [Google Scholar]
- 21.Devasenapathy N, Ghosh Jerath S, Sharma S, Allen E, Shankar AH, Zodpey S. Determinants of childhood immunisation coverage in urban poor settlements of Delhi, India: A cross-sectional study. BMJ Open. 2016;6:e013015. doi: 10.1136/bmjopen-2016-013015. [DOI] [PMC free article] [PubMed] [Google Scholar]