Interpregnancy Interval and Child Health Outcomes in India: Evidence from Three Recent Rounds of National Family Health Survey

INTRODUCTION: Short interpregnancy interval (IPI) is a well-known risk factor for preterm births and low birth weights. However, research on the association between interpregnancy interval (IPI) and health outcomes in children under age 5 is limited in India. We examined the associations between IPI and five child health outcomes in India. METHODS: We used nationally representative cross-sectional data from three rounds of National Family Health Survey (NFHS) conducted in India during 2005-06, 2015-16 and 2019-21 to examine the associations between IPI [categorized as < 12 months, 12–17 months, 18–23 months (ref), 24–35 months, and 36–59 months] and five child health outcomes – neonatal mortality, postneonatal mortality, diarrhea and/or acute respiratory infections (ARI), stunting, and underweight, for the total sample and, secondarily, using sex-stratified analyses. We used multivariable and mother fixed-effects binary logistic regressions to examine the associations. RESULTS: 3% and 2% of infants died during the neonatal and postneonatal period, respectively. Thirteen, 40, and 37% of children had diarrhea and/or ARI, were stunted, and were underweight, respectively. IPI < 12 months was associated with higher odds of diarrhea and/or ARI (OR: 1.11; 95% CI: 1.05–1.18), stunting (OR: 1.13; 95% CI: 1.08–1.18) and underweight (OR: 1.06; 95% CI: 1.01–1.11). Mother fixed-effects adjustments confirmed these associations and also found that births with IPI of 12–17 months and 36–59 months had higher odds of stunting, and IPI of 12–17 months was also associated with higher odds of underweight. DISCUSSION: Our findings indicate that IPIs shorter than 12 months are a risk factor for diarrhea and/or ARI, and IPIs shorter than 12 months and 12–17 months are risk factors for stunting and underweight among children under 5 in India. Mother fixed-effects models allowed us to adjust our estimates for unobserved heterogeneity; this has rarely been done before. Increases in birth spacing may improve child health outcomes in India.