The Effect of Adolescent Pregnancy on Child Mortality in 46 Low- and Middle-Income Countries

Introduction Adolescent pregnancy is a known health risk to mother and child. Statements and reports of health outcomes typically group mothers under 20 years old together. Few studies examined this risk at a finer age resolution, none of them comprehensively, and with differing results. Methods We analyzed Demographic and Health Surveys (DHS) data from 2004-2018 in Sub-Saharan Africa (SSA) and South Asia, on firstborn children of mothers 25 years old or younger. We examined the association between maternal age and stillbirths, and rates of neonatal (NNMR), infant (IMR), and under-5 mortality (U5MR), using mixed-effects logistic regression adjusting for major demographic variables and exploring the impact of maternal health-seeking. Results In both regions and across all endpoints, mortality rates of children born to mothers aged <16 years, 16-17 years, and 18-19 years at first birth were about 2-4 times, 1.5-2 times, and 1.2-1.5 times higher, respectively, than among firstborn children of mothers aged 23-25. Absolute mortality rates declined over time, but the age gradient remained similar across time periods and regions. Adjusting for rural/urban residence and maternal education, in SSA in 2014-2018 having a <16 year old mother was associated with odds ratio (ORs) of 3.71 [95% CI 2.50–5.51] for stillbirth, 1.92 [1.60–2.30] for NNMR, 2.13 [1.85–2.46] IMR, and 2.39 [2.13–2.68] U5MR, compared with having a mother aged 23-25. In South Asia in 2014-2018 ORs were 5.12 [2.85–9.20] stillbirth, 2.46 [2.03–2.97] NNMR, 2.62 [2.22–3.08] IMR, and 2.59 [2.22–3.03] U5MR. Part of the effect on NNMR and IMR may be mediated by a lower maternal health-seeking rate. Conclusions Adolescent pregnancy is associated with dramatically worse child survival and mitigated by health-seeking behavior, likely reflecting a combination of biological and social factors. Refining maternal age reporting will avoid masking the increased risk to children born to very young adolescent mothers. Collection of additional biological and social data may better reveal mediators of this relationship. Targeted intervention strategies to reduce unintended pregnancy at earlier ages may also improve child survival. What is already known? Most previous studies treat under-20 mothers as a single group when looking at risk of child health outcomes. Few studies have assessed the risk gradient versus age within this group, focusing only on neonatal and infant mortality rather than broader child survival outcomes. These studies found a higher risk of neonatal and infant mortality among younger adolescent mothers, even after adjusting for socio-economic, demographic and health service accessibility variables. The risk gradients for stillbirths and under-5 mortality outcomes of children born to adolescent mothers remain unexplored. What are the new findings? This is the most comprehensive, multi-regional study to-date that investigated the potential impacts of adolescent pregnancy, examining multiple child survival endpoints from stillbirths to under-5 mortality, and quantifying the risk gradient as a function of maternal age from adolescence through young adulthood. Children of mothers younger than 16 faced 2-4 times higher risk of death at all child mortality stages (stillbirths, neonatal, infant, and under-5) in both sub-Saharan Africa and South Asia regions. The association extends across socio-economic status (SES) groups in both urban and rural settings and stays consistent when controlling for maternal education and health seeking risk factors. What do the new findings imply? We recommend revision of maternal-age-group reporting conventions to make the increased child survival risk with adolescent pregnancy more visible. To improve child survival outcomes, improving health-seeking behavior and quality of maternal care, as well as targeted interventions to reduce unintended pregnancy among adolescents and mitigate its harmful consequences are needed. Collecting additional data on the social and biological aspects of adolescent pregnancy could help understand the impact size of these mediators on child health outcomes.