Adverse Perinatal and Neonatal Outcomes among Adolescent Pregnancies in the United States

Background: Despite a downward trend in recent years, adolescent pregnancies in the United States remain higher than any other Western country. Adolescent pregnancies have been inconsistently associated with adverse perinatal outcomes. Objective: To investigate the association between adolescent pregnancies and adverse perinatal and neonatal outcomes in the United States. Methods: This is a retrospective cohort study of singleton births in the US from 2014 to 2020 using national vital statistics data. Perinatal outcomes included gestational diabetes (GDM), gestational hypertension (gHTN), preterm delivery <37 weeks (PTB), cesarean delivery (CD), chorioamnionitis, small for gestational age (SGA), large for gestational age (LGA), and neonatal composite outcome. Chi-square tests were used to compare outcomes among adolescent (13-19 years) vs. adult (20-29 years) pregnancies. Multivariable logistic regression models were used to examine association of adolescent pregnancies with perinatal outcomes. For each outcome, we utilized three models: unadjusted logistic regression, adjusted for demographics, and adjusted for demographics and medical comorbidities. Similar analyses were used to compare younger (13-17 years) and older (18-19 years) adolescent pregnancies to adults. Results: In a cohort of 14,014,078 pregnancies, we found that adolescents were at an increased risk of PTB (adjusted odds ratio (aOR) 1.12, 99% confidence interval (CI)1.12-1.13) and SGA (aOR 1.02, 99% CI 1.01-1.03) compared to adult pregnancies. We also found that multiparous adolescents with a prior history of CD were at an increased risk of CD, compared to adults. For all other outcomes, adult pregnancies were at higher risk for adverse outcomes in the adjusted models. When comparing birth outcomes among adolescents, we found that older adolescents are at an increased risk of PTB, while younger adolescents are at an increased risk of both PTB and SGA. Conclusion: After adjusting for confounders, our study demonstrates adolescents have an increased risk of preterm birth and SGA, compared to adults.