Association between risk of mortality among children and twin birth in India: an econometric analysis of live births between 1993-2021.

BACKGROUND

Twin births present unique challenges for child survival, particularly in low- and middle-income countries. Despite the high burden of global child mortality, there has been no comprehensive assessment of twin births and deaths in India. We analysed the trends and patterns in twin births and deaths in India between 1993 and 2021, examining mortality risks across different phases of early childhood, including the late neonatal phase.

METHODS

We analysed data on 659 175 births from five rounds of India's National Family Health Survey (NFHS) (1992-93 to 2019-21). We calculated age-specific mortality rates using a synthetic cohort life table approach for early neonatal (0-7 days), late neonatal (8-28 days), post-neonatal (29 days to 11 months), and child (12-59 months) periods. The analysis employed logistic regression models (both adjusted and unadjusted) to estimate phase-specific mortality risks and coarsened exact matching to establish causal relationships while adjusting for demographic and socioeconomic covariates.

RESULTS

Twinning rates in India increased from 0.9% in 1992-93 to 1.5% in 2019-21. Despite this small share in births, twins accounted for 7.7% of under-five deaths in 2019-21. Twin under-five mortality rate was 179.8 (95% confidence interval (CI) = 162.2, 197.4) per 1000 live births in 2019-21, declining from 447.5 (95% CI = 405.6, 489.3) in 1992-93. Twins faced 7.5 times higher risk of early neonatal death and 10 times higher risk of late neonatal death compared to singletons. Twins from the poorest wealth quintile experienced 9.8 (95% CI = 8.43, 11.44) times higher early neonatal mortality risk compared to those from the highest quintile. The coarsened exact matching analysis confirmed twin birth as an independent risk factor for neonatal and infant mortality.

CONCLUSIONS

Despite general improvements in child survival, twin mortality rates continue to be high, particularly during the neonatal period. The persistent socioeconomic gradient in twin survival necessitates strengthening health care delivery for vulnerable populations. Establishing twin registries and including twin mortality in global monitoring frameworks could accelerate progress toward achieving Sustainable Development Goal targets for child survival.