Reproductive health among married and unmarried mothers aged less than 18, 18–19, and 20–24 years in the United States, 2014–2019: A population-based cross-sectional study

Abstract

Background Studies in low- and middle-income regions suggest that child marriage (Methods and findings Birth registrations with US resident mothers aged ≤24 years with complete information on marital status were drawn from the 2014 to 2019 Natality Public Use Files (n = 5,669,824). Odds ratios for the interaction between marital status and maternal age group were estimated using multivariable logistic regression, adjusting for covariates such as maternal race/ethnicity and nativity status, federal program participation, and paternal age. Marriage prevalence was 3.6%, 13.2%, and 34.1% among births to mothers aged Conclusions Marriage among mothers below age 18 is associated with both adverse and favorable reproductive, maternal, and infant health indicators. Heterogeneity exists in the relationship between marriage and reproductive health across adolescent maternal age groups, suggesting girl child marriages must be examined separately from marriages at older ages. In a population-based study, Andrée-Anne Fafard St-Germain and colleagues examine the joint associations of marriage and adolescent maternal age group (Why was this study done? Research in low- and middle-income countries indicates that child marriage, namely marriage before age 18 years, has negative implications for the reproductive health and well-being of women compared to marriage at an older age. In high-income countries where childbearing increasingly occurs outside marriage, it is unclear how marriage among mothers below age 18 relates to different indicators of reproductive health. Studies in high-income countries show that marriage is associated with positive reproductive health outcomes, but it is unknown whether these beneficial associations apply to mothers below age 18. What did the researchers do and find? We analyzed cross-sectional information from more than 5.5 million birth registrations with mothers aged ≤24 years in the United States from 2014 to 2019 to examine how marriage and maternal age jointly relate to reproductive health. Marriage was associated with increased odds of prior pregnancy termination, repeat childbearing, maternal smoking, and infant morbidity among births to mothers below age 18, but the association of marriage with these indicators was weaker or reversed among births to older mothers. Protective associations with marriage were observed for preterm birth, small-for-gestational-age birth, sexually transmitted infection, prenatal care initiation, and breastfeeding among births to mothers aged 20–24 years, but for births to mothers aged What do these findings mean? Our study indicates that the health advantage of marriage observed among mothers aged 20–24 years in the United States may not consistently apply to younger mothers. It suggests that the association between marriage below age 18 and reproductive health indicators is context- and outcome-dependent. Although this study cannot establish causation, it suggests the need for further research on the driving forces and the health and social consequences of marriage before age 18 in the US and other high-income countries, and that such research may benefit from longitudinal study designs.