Pregnancy outcomes among mothers aged 15 years or less

The aim of this study was to determine pregnancy outcomes among early adolescent women (aged ≤ 15 years) compared with those in late adolescence (16-19 years) and adults aged 20-30 years.

A retrospective cohort study was conducted on singleton pregnancies with maternal age ≤15 years (early adolescent), 16-19 years (late adolescent), and 20-30 years (adult). The primary outcomes for comparison were the rates of preterm birth, low birthweight, growth restriction and cesarean section.

A total of 33 777 pregnancies, 298 early adolescent, 4456 late adolescent, and 29 023 adults, were enrolled. Most baseline characteristics were comparable but rates of pregnancy complicated by medical diseases were significantly higher in the adults, especially diabetes mellitus and chronic hypertension. When compared to the adult group, the early adolescent group had significantly higher rates of preterm birth (31.9% vs 14.5%, P < 0.001), growth restriction (11.7% vs 7.1%, P = 0.002), low birthweight (28.9% vs 14.7%, P < 0.001), while maternal morbidity, such as pre-eclampsia and placenta previa, was similar. Likewise, most of the main outcomes in early adolescents were also significantly higher than those in late adolescents, but with lesser degrees. Interestingly, the primary cesarean rate was significantly lower in early adolescent women (6.7% vs 12.3%, P = 0.005).

Early adolescent pregnancy was associated with higher risks of adverse pregnancy outcomes, in particular preterm birth and growth restriction, though most maternal morbidity was comparable with that in the control groups. Cesarean rate was significantly lower in early adolescent mothers. This information should be provided to women and their families.