Comparing pregnancy and pregnancy outcome rates between adolescents with and without pre-existing mental disorders.

BACKGROUND: There are limited population-based data on the role of mental disorders in adolescent pregnancy, despite the presence of mental disorders that may affect adolescents' desires and decisions to become pregnant.

OBJECTIVE: This study aimed to examine the relationship between specific types of mental disorders and pregnancy rates and outcome types among adolescents aged 13-19 years, using single-year age groups.

METHODS: We conducted a retrospective cohort study using data from the Merative™ MarketScan Research Databases. The study population consisted of females aged 13-19 years with continuous insurance enrollment for three consecutive calendar years between 2005 and 2015. Pregnancy incidence rates were calculated both overall and within the different categories of mental disorders. The presence of mental disorders, identified through diagnosis codes, was classified into 15 categories. Pregnancy and pregnancy outcome types were determined using diagnosis and procedure codes indicating the pregnancy status or outcome. To address potential over- or underestimations of mental disorder-specific pregnancy rates resulting from variations in age distribution across different mental disorder types, we applied age standardization using 2010 U.S. Census data. Finally, multivariable logistic regression models were used to examine the relationships between 15 specific types of mental disorders and pregnancy incidence rates, stratified by age.

RESULTS: The age-standardized pregnancy rate among adolescents diagnosed with at least one mental disorder was 15.4 per 1,000 person-years, compared to 8.5 per 1,000 person-years among adolescents without a mental disorder diagnosis. Compared to pregnant adolescents without a mental disorder diagnosis, those with a mental disorder diagnosis had a slightly but significantly higher abortion rate (26.7% vs 23.8%, P-value < 0.001). Multivariable logistic regression models showed that substance use-related disorders had the highest odds ratios (ORs) for pregnancy incidence, ranging from 2.4 [95% confidence interval (CI): 2.1-2.7] to 4.5 [95% CI:2.1-9.5] across different age groups. Overall, bipolar disorders (OR range: 1.6 [95% CI:1.4-1.9]- 1.8 [95% CI: 1.7-2.0]), depressive disorders (OR range: 1.4 [95% CI: 1.3-1.5]- 2.7 [95% CI: 2.3-3.1]), alcohol-related disorders (OR range: 1.2 [95% CI: 1.1-1.4]- 14.5 [95% CI: 1.2-178.6]), and attention-deficit/conduct/disruptive behavior disorders (OR range: 1.1 [95% CI: 1.0-1.1]- 1.8 [95% CI: 1.1-3.0]) were also significantly associated with adolescent pregnancy, compared to adolescents without diagnosed mental disorders of the same age.

CONCLUSION: This study emphasizes the elevated rates of pregnancy and pregnancy ending in abortion among adolescents diagnosed with mental disorders, and identifies the particular mental disorders associated with higher pregnancy rates.