Time trends and sociodemographic inequalities in the prevalence of adolescent motherhood in 74 low-income and middle-income countries: a population-based study

Background Documenting trends and inequalities in the prevalence of adolescent motherhood across low-income and middle-income countries (LMICs) is important to support the adolescent sexual and reproductive health target in the UN Sustainable Development Goals (SDGs). We aimed to examine time trends and sociodemographic inequalities in the prevalence of adolescent motherhood in LMICs. Methods We analysed data from 747 137 young women (aged 15-19 years) from 74 LMICs, using 254 nationally representative Demographic and Health Surveys done between 1990 and 2018. We estimated the population-weighted prevalence of adolescent motherhood among women aged aged 15-19 years (defined as having had a livebirth or being pregnant at the time of the survey). Trends in the prevalence were calculated at the national level using the average annual rate of change (AARC) in a subset of 61 countries with at least two surveys from different timepoints during the study period. Sociodemographic inequalities (eg, wealth quintile, level of education, and rural or urban residence) in adolescent motherhood were described using the normalised concentration index. Findings The highest prevalence of adolescent motherhood was observed in sub-Saharan African countries, for example it was 36.00% (95% CI 33.98-38.08) in Mali (which had recent survey data; 2018). Examining AARC, countries such as Nigeria (AARC -1.35%; 1990-2018) and India (-4.62%; 1992-2015) experienced a steady decline in the prevalence of adolescent motherhood during the study period. However, several high-burden countries experienced little change in prevalence over time (-0.60%; Bangladesh, 1993-2014), and 16 countries, such as Cambodia (2.42%; 2000-14) and Philippines (1.59%; 1993-2017), had an increase in the prevalence of adolescent motherhood over time. Sociodemographic inequalities in the prevalence of adolescent motherhood persist in most countries in this study. Interpretation Many of the countries in this study experienced either a slow rate of reduction or an increase in the prevalence of adolescent motherhood during the study period, and sociodemographic inequalities within countries persist. These results indicate that efforts to reduce adolescent motherhood and the associated health burden need to be improved within many LMICs. These findings can assist policy makers to target the rollout of interventions on the basis of observed geographic and sociodemographic inequalities to reduce adolescent motherhood among the disadvantaged, and accelerate progress towards adolescent sexual and reproductive health targets in the UN SDGs. Copyright (C) 2020 Elsevier Ltd. All rights reserved.