Frequently Asked Questions

Maternal ADHD in pregnancy increased more than 4-fold over the study period. In this Ontario cohort, the proportion of pregnancies with maternal ADHD rose from 0.5% in 2002 to 2.5% in 2023 when ADHD was defined as a diagnosis within 10 years before conception. Using a narrower definition of current ADHD, the proportion increased from 0.1% to 1.3% over the same period.

By 2023, 1 in 40 pregnancies had a maternal ADHD diagnosis in this study. That corresponds to 2.5% of pregnancies when maternal ADHD was defined as at least 1 recorded diagnosis within 10 years before conception.

Yes. Among pregnancies with maternal ADHD, stimulant use during pregnancy increased from 10.1% in 2014 to 20.9% in 2023 for the broader any-ADHD group. In the year before pregnancy, stimulant prescribing also increased, from 21.8% to 39.8% over the same period.

Lisdexamfetamine showed the largest increase over time and became the most prevalent ADHD medication in pregnancy by the end of the study period. Its use increased from 2.6% to 10.0% during pregnancy and from 5.7% to 19.9% in the year before pregnancy between 2014 and 2023. Methylphenidate and lisdexamfetamine were the most frequently used stimulants overall, followed by amphetamine and dextroamphetamine.

Yes. Stimulant use was highest in the first trimester throughout the study period. For pregnancies with any maternal ADHD, first-trimester stimulant use increased from 9.6% in 2014 to 19.3% in 2023, and use also increased over time in the second and third trimesters.

In this study, most women with preconception stimulant use discontinued before conception or in the first trimester. In 2023, among those with stimulant use in the preconception year and any maternal ADHD, about 75% stopped before conception or in T1: 50.5% discontinued before conception and 24.6% discontinued in the first trimester. An additional 3.6% discontinued in the second trimester, 15.9% continued throughout pregnancy, and 5.5% later reinitiated treatment.

Compared with pregnant women without ADHD, pregnant women with ADHD were younger, more often primiparous, more likely to live in lower-income neighborhoods, and more likely to have psychiatric comorbidity. The median maternal age was 23 versus 31 years, 56.1% versus 42.9% were primiparous, 33.1% versus 19.6% were in the lowest neighborhood income quintile, and 86.8% versus 42.9% had psychiatric history.

This was a cross-sectional time series analysis using Ontario health administrative data. The cohort included 2,327,110 obstetrical deliveries, defined as live births or stillbirths over 20 weeks gestation, with estimated pregnancy starts between April 1, 2002, and March 31, 2024. Pregnancies ending in miscarriage or abortion were not included.

Maternal ADHD was defined as at least 1 recorded ADHD diagnosis in health administrative data within 10 years before conception, and current maternal ADHD was defined as at least 1 diagnosis within 3 years before conception. Stimulant use was defined by at least 1 filled prescription overlapping the relevant time window: the preconception year for pre-pregnancy use, or the period from conception to childbirth for pregnancy use. The stimulants studied were amphetamine, dexamphetamine, methylphenidate, and lisdexamfetamine.

The study has several limitations that affect interpretation. It did not include nonstimulant ADHD medications such as atomoxetine, so total ADHD medication use may be underestimated. It included only pregnancies ending in obstetrical delivery, not miscarriage or abortion; defined medication exposure using filled prescriptions, which may miss medication supplied before conception; and may have misclassified ADHD if diagnoses occurred before immigration to Ontario or were made by a psychologist without a recorded administrative diagnosis.

This study did not directly test medication safety outcomes, but it states that safety data for ADHD medications in pregnancy remain limited. The authors note that most existing reproductive safety data concern methylphenidate, which has not been associated with major increased risk of miscarriages, congenital anomalies, or long-term neurodevelopmental disorders, although it may carry a small risk of cardiac malformations and preterm birth. They also emphasize that lisdexamfetamine became the most commonly prescribed stimulant in pregnancy by the end of the study period despite a paucity of pregnancy safety data.