Pregnancy Outcomes in Women Diagnosed With Attention-Deficit/Hyperactivity Disorder: A Population-Based Register Study.

Background: Maternal attention-deficit/hyperactivity disorder (ADHD) has been associated with various pregnancy outcomes, but the degree to which that association is explained by concomitant mental disorders and smoking during pregnancy remains unclear.

Objective: To investigate the association between maternal ADHD and pregnancy outcomes.

Methods: Through the Swedish Medical Birth Register, we identified 977,266 women who gave birth to a live singleton between January 1, 2006, and December 1, 2020 (1,617,121 pregnancies). Of these, 1.3% (12,553 women; 17,434 pregnancies) had an ADHD diagnosis prior to pregnancy. The primary outcome was preterm birth (< 37 weeks), with secondary outcomes being postterm birth (> 41 weeks), small for gestational age, large for gestational age, birth weight (≤ 2500, 2501-3500, > 4500 g), acute and planned cesarean section, assisted vaginal delivery, preeclampsia, and gestational diabetes. Generalized linear mixed-effects models adjusted for maternal age, year of childbirth, maternal education, comorbid mental disorders, and smoking during pregnancy.

Results: There were 1089 (6.6%) preterm births among women with ADHD, and 73,423 (4.9%) preterm births among women without an ADHD diagnosis, corresponding to a crude OR of 1.33 (95% CI 1.25, 1.42). This association attenuated to nonsignificance after adjusting for maternal age, year of childbirth, maternal education, and comorbid mental disorders (adjOR = 1.06, 95% CI: 0.99, 1.13). Fully adjusted models revealed that ADHD was associated with an increased risk of having a large for gestational age baby (adjOR = 1.16, 95% CI: 1.06, 1.26) and undergoing a planned caesarean section (adjOR = 1.16, 95% CI: 1.06, 1.26). Sensitivity analyses using a broader ADHD definition suggested associations with preterm birth (adjOR = 1.09, 95% CI: 1.04, 1.15) and acute caesarean section (adjOR = 1.09, 95% CI: 1.04, 1.13).

Conclusions: After adjustments for comorbid mental disorders and smoking during pregnancy, maternal ADHD was not associated with preterm birth. An increased risk of delivering large for gestational age babies and undergoing planned caesarean sections was found in women with ADHD.