Maternal attention deficit hyperactivity disorder and adverse obstetrical and perinatal outcomes: a population-based cohort study in Ontario, Canada

Background — A growing number of young women are diagnosed with attention-deficit/hyperactivity disorder (ADHD), yet, little is known about their pregnancy outcomes.

Objective — To examine the association between a preconception diagnosis of maternal attention/deficit-hyperactivity disorder (ADHD) and adverse obstetrical and perinatal outcomes.

Study design — This population-based cohort study comprised all hospital births in Ontario, Canada, 2013 to 2023. Individuals with and without preconception ADHD were compared. Modified Poisson regression generated relative risks (RR) for the outcomes of severe maternal morbidity (SMM) and severe neonatal morbidity (SNM) composite indicators. Secondary outcomes included hypertensive disorders of pregnancy, gestational diabetes mellitus (GDM), stillbirth, preterm birth < 37 weeks, small for gestational age birthweight (SGA), and neonatal mortality.

Results — Among 1,051,033 obstetrical deliveries, 22,995 (2.2%) had a diagnosis of ADHD before conception. SMM occurred among 640 individuals with ADHD (2.8%) vs. 23,578 (2.3%) without ADHD (aRR 1.31, 95% CI 1.21-1.42). SNM occurred at respective rates of 15.7% and 12.5% (aRR 1.25, 95% CI 1.21-1.29). Maternal ADHD was also associated with elevated aRRs for preeclampsia (1.28, 95% CI 1.18-1.38), preterm birth (1.41, 95% CI 1.35-1.47), and SGA (1.21, 95% CI 1.15-1.26), but not GDM (0.98, 95% CI 0.93-1.03), stillbirth (0.81, 95% CI 0.69-0.96), or neonatal mortality (1.09, 95% CI 0.83-1.43). After removing individuals who filled a psychostimulant prescription during pregnancy, the findings were largely unchanged.

Conclusions — A preconception diagnosis of maternal ADHD is associated with a higher risk of certain adverse obstetrical and perinatal outcomes. These patients may benefit from enhanced supports and a care plan aimed at optimizing pregnancy outcomes.