Driving Factors of Preterm Birth Risk in Adolescents

Objective  We examined rates of spontaneous and indicated preterm births (S-PTB and I-PTB, respectively) and clinical risk factors for PTB in adolescents. Study Design  This is a population-based, retrospective cohort using 2012 U.S. natality data of nulliparous women who delivered a nonanomalous singleton birth between 20 and 42 weeks' gestation. Maternal age included <16, 16 to 19.9, and ≥20 years. Rates of total, S-PTB, and I-PTB were compared across age groups. Multinomial logistic regression tested clinical risk factors for S-PTB. Results  In 1,342,776 pregnancies, adolescents were at higher risk for PTB than adults. The rate of total PTB was highest in young adolescents at 10.6%, decreased to 8.3% in older adolescents, and 7.8% in adults. The proportion of S-PTB was highest in the youngest adolescents and decreased toward adulthood; the proportion of I-PTB remained stable across age groups. Risk factors for S-PTB in adolescents included Asian race, underweight body mass index (BMI), and poor gestational weight gain (GWG). In all age groups, carrying a male fetus showed a significant increased S-PTB, and Women, Infants, and Children's (WIC) participation was associated with a significantly decreased risk. Conclusion  The higher risk for PTB in adolescents is driven by an increased risk for S-PTB. Low BMI and poor GWG may be potentially modifiable risk factors. Condensation  Adolescents have a higher risk for spontaneous PTB than adult women, and risk factors for spontaneous PTB may differ in adolescents.