Adolescent Pregnancies in the United States: How Obstetric and Sociodemographic Factors Influence Risk of Cesarean Delivery.

 To determine how an adolescent's risk of cesarean varies by maternal age and race/ethnicity, and evaluate the contribution of obstetric and sociodemographic factors to mode of delivery.  This is a retrospective cohort study of 604,287 births to women aged 13 to 23 years. Regression techniques were used to determine maternal ages at lowest risk of primary cesarean in each major racial/ethnic group before and after adjustment for various cesarean risk factors.  Adolescent age was associated with lower risk of cesarean compared with young adults (17.2% at age 13 years vs 24.8% at age 23 years,  < 0.05). After stratification by race/ethnicity, Non-Hispanic Black women had the highest probability of cesarean, while Asian/Pacific Islanders had the lowest probability across all ages. When compared with young adults of the same race/ethnicity, young adolescents continued to have a lower risk of cesarean, decreased by at least 30% until age 18 years (White) and 17 years (other racial/ethnic groups). These associations persisted after adjustment for obstetric and sociodemographic risk factors.  Young maternal age is protective against cesarean delivery in all racial/ethnic groups. Adolescents also experience racial/ethnic disparities in mode of delivery similar to those observed in adults, which were unexplained by either obstetric or sociodemographic factors.