Objective: To evaluate whether psychostimulants used to treat attention-deficit/hyperactivity disorder (ADHD) are associated with risk of adverse placental-associated pregnancy outcomes including preeclampsia, placental abruption, growth restriction, and preterm birth.
Methods: We designed a population-based cohort study in which we examined a cohort of pregnant women and their liveborn neonates enrolled in Medicaid from 2000 to 2010. Women who received amphetamine-dextroamphetamine or methylphenidate monotherapy in the first half of pregnancy were compared with unexposed women. We considered atomoxetine, a nonstimulant ADHD medication, as a negative control exposure. To assess whether the risk period extended to the latter half of pregnancy, women who continued stimulant monotherapy after 20 weeks of gestation were compared with those who discontinued. Risk ratios and 95% CIs were estimated with propensity score stratification to control for confounders.
Results: Pregnancies exposed to amphetamine-dextroamphetamine (n=3,331), methylphenidate (n=1,515), and atomoxetine (n=453) monotherapy in early pregnancy were compared with 1,461,493 unexposed pregnancies. Among unexposed women, the risks of the outcomes were 3.7% for preeclampsia, 1.4% for placental abruption, 2.9% for small for gestational age, and 11.2% for preterm birth. The adjusted risk ratio for stimulant use was 1.29 for preeclampsia (95% CI 1.11-1.49), 1.13 for placental abruption (0.88-1.44), 0.91 for small for gestational age (0.77-1.07), and 1.06 for preterm birth (0.97-1.16). Compared with discontinuation (n=3,527), the adjusted risk ratio for continuation of stimulant use in the latter half of pregnancy (n=1,319) was 1.26 for preeclampsia (0.94-1.67), 1.08 for placental abruption (0.67-1.74), 1.37 for small for gestational age (0.97-1.93), and 1.30 for preterm birth (1.10-1.55). Atomoxetine was not associated with the outcomes studied.
Conclusion: Psychostimulant use during pregnancy was associated with a small increased relative risk of preeclampsia and preterm birth. The absolute increases in risks are small and, thus, women with significant ADHD should not be counseled to suspend their ADHD treatment based on these findings.