In a study led by researchers from the International Institute for Population Sciences, Mumbai, in collaboration with the University of California, San Diego, the association between interpregnancy intervals (IPI) and five child health outcomes—neonatal mortality, post-neonatal mortality, diarrhea, and/or acute respiratory infections (ARI), stunting, and underweight—was examined.

The findings of the study published in the journal Maternal and Child Health Journal revealed that "interpregnancy intervals" (IPI) shorter than 12 months were associated with the risk of diarrhea and/or acute respiratory infections, while IPIs shorter than 17 months were associated with the risk of stunting and underweight among children under 5 in India. Moreover, the study showed that 4% of infants with IPIs younger than 12 months died within 28 days of birth.

According to an analysis of the National Family Health Survey data from 2005–06, 2015–16, and 2019–21, only 2% of infants with IPIs ages 18–23 months died within 28 days of birth. The data from the national survey conducted between 2019 and 21 showed that 32% and 19% of children under age 5 were underweight and wasted, respectively.

The data from the NFHS-3, NFHS-4, and NFHS-5 surveys showed that 3% and 2% of infants died during the neonatal and post-neonatal periods, respectively. On the other hand, 13%, 40%, and 37% of children had diarrhea and/or ARI, stunting, and were underweight, respectively.

The cumulative data from all three national surveys revealed that the prevalence of recent diarrhea ranged between 13% among children with an IPI of less than 12 months and 14% among children with an IPI of 36–59 months. Meanwhile, 43% and 38% of children born with an IPI shorter than 12 months were stunted and underweight, respectively. In comparison, only 28% and 27% of children born with an IPI of 36–59 months were stunted and underweight, respectively.

Additionally, it was deduced that infant girls were less likely to die during the neonatal period compared to infant boys. The study found that male and female infants with IPIs less than 12 months had a higher risk of neonatal and post-neonatal mortality. But the overall risk of neonatal mortality was higher among infant girls with IPIs of 12–17 months. 

(Source: https://timesofindia.indiatimes.com/india/longer-interpregnancy-interval-the-key-to-reducing-infant-mortality-stunting/articleshow/96042253.cms? )