Perinatal outcomes of young adolescent pregnancies in an urban inner city

Although substantial efforts have been made to reduce the rates of adolescent pregnancy, the United States continues to have higher rates than other industrialized countries. Research and reporting usually focus on adolescents aged 15 to 19 years. Although less common, there are pregnant young adolescents that are ≤15 years of age, with developmental and social differences from older, high school-aged adolescents.

Because adolescent pregnancies are of particular concern because of long-term socioeconomic consequences to parent and child, we sought to determine whether young adolescents (≤15 years old) had worse perinatal outcomes than older adolescents (16-19 years old) and older parents (≥20 to 34 years old) among those living in an urban inner city.

This was a study of pregnant individuals who delivered a singleton pregnancy without evidence of chronic hypertension or pregestational diabetes mellitus at a safety net hospital from January 2010 to May 2021. Parents were grouped by age at the time of delivery into young adolescents (≤15 years old) and older adolescents (16-19 years old). For a comparison group, nulliparous older parents aged 20 to 34 years with singleton pregnancies were analyzed for perinatal outcomes and compared with the adolescent cohorts. When analyzing baseline parental characteristics, a preponderance of obesity was noted in the young adolescent cohort. An analysis of parental characteristics and perinatal outcomes among young adolescents with obesity vs young adolescents without obesity ≤15 years old was performed. Statistical analysis included χ² and Student t test with P values of <.05 considered significant. Logistic regression analysis was performed to control for potentially confounding demographic variables.

Overall, 10,894 adolescent women delivered, with 868 young adolescents and 10,026 older adolescents. Pairwise comparisons showed young adolescents had a different race distribution than older adolescents (P=.006) and older parents (P<.001). Young adolescents were more likely to be Hispanic or non-Hispanic Black (P<.001) and accessed prenatal care at a later gestational age (19.7±8.9 weeks) compared with older adolescents (16.7±8.6 weeks) and the comparison older cohort of parents (15.7±8.7 weeks) (P<.001) and less frequently in pregnancy (P<.001) compared with older parents. Young adolescents were more likely to have preterm birth at <37 weeks of gestation (P<.001) and eclampsia (0.5% vs 0.1%) (P=.01) than older adolescents. Therefore, low birthweights of ≤2500 g (P=.02) and neonatal intensive care unit admission (P=.048) were also increased in adolescents. When adjusted for race, ethnicity, and body mass index, preeclampsia with severe features (P<.001) and preterm birth at <37 weeks of gestation (P=.048) remained significant. Young adolescents with obesity were more likely to have preeclampsia with severe features (odds ratio, 1.81; 95% confidence interval, 1.22-2.68) and be delivered via cesarean delivery (odds ratio, 2.71; 95% confidence interval, 1.85-3.99) than adolescents without obesity.

In an urban inner city, young adolescent parents were more likely to be women of color, have later presentations to prenatal care, and have increased rates of preterm birth. Young adolescents had high rates of obesity, which was associated with increased rates of hypertensive disorders of pregnancy and cesarean delivery, than adolescents without obesity.