Risk of teenage pregnancy among adolescents with bipolar disorder: a cohort study of 35,398 adolescent girls.

Teenage pregnancy is a major public health concern. However, few studies have investigated the relationship between pediatric bipolar disorder and early pregnancy, and whether bipolar disorder medications reduce the risk of early pregnancy remains unknown. In total, 3218 adolescent girls with bipolar disorder and 32,180 controls matched for age, family income, residence, and time of enrollment were enrolled in this study from 2001 to 2009. Early pregnancy, defined as pregnancy occurring in patients younger than 20 years old, was identified during the follow-up period from enrollment until the end of 2011. After adjustment for demographic data, psychiatric comorbidities, and bipolar disorder medications, adolescent girls with bipolar disorder had 20 times the risk of early pregnancy (hazard ratio [HR] = 20.63, 95% confidence interval [CI] [15.68, 27.16]) and about 25 times the risk of repeated early pregnancy (HR = 24.59, 95% CI [15.20, 39.78]) compared with those without bipolar disorder. Long-term use of both mood stabilizers (HR = 0.34, 95% CI [0.23, 0.52]) and atypical antipsychotics (HR = 0.32, 95% CI [0.20, 0.51]) was associated with a reduced risk of early pregnancy. Bipolar disorder was associated with an increased risk of early pregnancy in adolescent girls. Bipolar disorder medications reduced this risk. The results suggest that interventions targeting the vulnerable population of adolescent girls with bipolar disorder are warranted to prevent early pregnancies.