Alarming disparities of adolescent motherhood in Nigeria: results from 36 states and the Federal Capital Territory

IMPORTANCE: Nigeria has a population of 233 million people and high rates of adolescent motherhood. Reduction of adolescent motherhood is a priority and primarily aligns with the sexual and reproductive health target (indicator 3.7.2) in the specific United Nations Sustainable Development Goals (SDGs). OBJECTIVE: This study examined the trends and social disparities of health impacting adolescent motherhood at the state level. DESIGN, SETTINGS AND PARTICIPANTS: The study analysed 24 668 adolescent females aged 15-19 years, drawn from 36 states and the Federal Capital Territory (FCT) using four Nigerian Demographic and Health Surveys (2003-2018). This study estimated the population-weighted prevalence of adolescent motherhood and employed the average annual rate of change (AARC) to compute the state-level trends in the prevalence. The normalised concentration index was also used to understand the sociodemographic inequalities. RESULTS: The national prevalence of adolescent motherhood is 18.73%, with substantial variation in AARC and a normalised concentration index across states in different geopolitical zones. The highest prevalence of adolescent motherhood was observed in Bauchi State in the North-East at 40.65%, while the lowest was in Lagos in the South-West at 1.1%. The AARC in Bauchi was +1.7%, while in Lagos it was reported at -9.96%. Out of the 36 states and FCT, 15 (40.5%) either experienced an increasing prevalence of adolescent motherhood (29.7%) or a slow decline (10.8%) while 22 (59.5%) showed progress. With respect to the distribution of adolescent motherhood, most of the high-burden states had a negative normalised concentration index for wealth (92%), education (92%) and area of residence (72%). Moreover, highly statistically significant variations were observed between high-burden states in the North and low-burden states in the South for wealth, education, rurality, child marriage, age at first child and polygyny. CONCLUSIONS: Adolescent motherhood remains persistently high in Nigeria, particularly in the northern part of the country, due to early marriage, intergenerational poverty and a lack of education. This necessitates scaling up state-specific health education programmes targeting adolescent girls in schools and government policy, enforcing the legal age of marriage to achieve the SDG 3.7.2 target.