The Neonatal Mortality Risk of Different Types of Vulnerable Newborns in Rural Bangladesh: A Prospective Cohort Study Within the Shonjibon Trial

OBJECTIVES: We aimed to estimate the prevalence and neonatal mortality risks associated with mutually exclusive vulnerable newborn phenotypes in rural Bangladesh. METHODS: We conducted a prospective cohort study in five rural districts in Bangladesh using data collected on births in the Shonjibon Trial from 2013–2015. We estimated the prevalence of preterm birth, low birth weight (LBW), small-for-gestational-age (SGA), and large-for-gestational-age (LGA) individually and for mutually exclusive phenotypes using a combination of these characteristics. We calculated the neonatal mortality associated with preterm birth, LBW, SGA, LGA, and mutually exclusive phenotypes using Kaplan-Meier survival analysis for neonatal mortality rates and Poisson regression for adjusted relative risks (aRR) with 95% confidence intervals (CI). RESULTS: We analyzed 24,314 live births and found the prevalence of preterm birth was 26.2%, LBW 22.9%, SGA 41.7%, and LGA 8.2%. The neonatal mortality risk was approximately 3-fold for preterm birth, LBW, and LGA, and 1.5-fold higher for SGA compared to newborns with appropriate-for-gestational-age (AGA), with term gestation (≥37 weeks) and normal birth weight (NBW, ≥2500g). The risk of neonatal mortality was highest in infants born SGA, preterm, and LBW (aRR = 6.3 95% CI 4.1–9.6) relative to AGA, term, and NBW infants. There was an increased mortality risk for vulnerable newborns whose households had any iron in their drinking water. CONCLUSIONS: In rural Bangladesh, most infants are born with one or more vulnerable newborn characteristics associated with an increased risk of neonatal mortality. Groundwater iron may exacerbate this risk. Our findings highlight the value of categorizing infants using mutually exclusive vulnerable newborn phenotypes and their different neonatal mortality risks, which will help to target nutrition interventions to improve child survival. FUNDING SOURCES: National Health and Medical Research Council, Australia.