Trends in childhood viable pregnancy and risk of stillbirth in the United States

There is limited data on the trends of childhood viable pregnancy and the risk of stillbirth in the United States. Our study assessed the trends in childhood viable pregnancy and associated stillbirth rates over the previous three decades, as well as the risk of stillbirth in these highly vulnerable child mothers aged 10-14 compared with teen mothers aged 15-19. We conducted a population-based retrospective cohort study that used birth datasets, fetal death datasets, and the US population census data: 1982-2017. To assess the association between various sociodemographic and maternal comorbidities and stillbirth, we generated adjusted hazard ratios (AHR) from Cox proportional hazards regression models. From 1982 to 2017, viable pregnancy rates declined among children (from 0.3/1000 to 0.06/1000 population) and teens (from 40.5/1000 in 1982 to 18.1/1000). Overall, there were declines in the stillbirth rates in both teens (15-19 years old) and child mothers aged 10-14 years, but the rate remained consistently higher among child mothers vs. teen mothers (14 per 1000 vs. 8 per 1000 viable pregnancies). Compared to teen mothers, childhood pregnancy was modestly associated with an elevated risk for stillbirth (AHR = 1.09; 95% CI = 1.05-1.12). Other factors significantly associated with increased risk of stillbirth included maternal race, preterm birth, arterial hypertension, diabetes, and eclampsia (P<0.0001). Conclusion: Childhood pregnancy may be a risk factor for stillbirth. This is the first study to assess the trends in childhood viable pregnancy and the associated stillbirth rates in the United States. These findings further underscore the need for sustained efforts and policies to prevent pregnancies in the early years of reproductive development.