(F) ADHD Medication Use Trajectories Among Pregnant Women with ADHD in Norway and Sweden

Publication Number: 296

Background: Medications to treat attention-deficit hyperactivity disorder (ADHD) are increasingly used among adults. There is limited research describing patterns of ADHD medication use in pregnancy and lactation.

Objectives: The objectives of this study were to describe ADHD prescription fill trajectories 12 months before, during, and 12 months after pregnancy and the characteristics of users associated with each trajectory in Norway and Sweden.

Methods: We identified pregnancies resulting in births at 22-44 gestational weeks using linked data from the birth and prescribed drug registers of Norway (N=829,793) and Sweden (N=1,287,783) between 2006-2019. We restricted to women who filled one or more prescriptions for ADHD medication (amphetamine, dexamphetamine, methylphenidate, atomoxetine, lisdexamfetamine, guanfacine) from 12 months before pregnancy, during pregnancy, and 12 months after delivery. We used group-based trajectory modeling to identify distinct trajectory patterns. The model that provided the best fit was chosen based on quality criteria (Bayesian information criterion) and clinical relevance. We then compared the characteristics of women in each group, including any use of other psychotropics during the period of interest.

Results: In total, 13,286 filled a prescription for ADHD medication during pregnancy or in the year before or after. We identified four distinct trajectory groups: continuers (5%), interrupters (24%), discontinuers (50%), and post-pregnancy initiators (21%). Discontinuers tended to be younger, and continuers tended to be older on average. The proportion of continuers was higher among pregnancies in recent years (2014-2019) than before. Most discontinuers (61% vs 52% overall) had not given birth previously, whereas more initiators and continuers had a single or multiple previous births, respectively, than other groups. Continuers were least likely to live with a partner (65% vs 72% overall). Discontinuers were the least likely (25%) and continuers the most likely (39%) to smoke at the beginning of pregnancy. While methylphenidate was the most used drug overall (85%), fewer continuers (82%) used it, and they were more likely to use amphetamine and its derivatives than other groups. Continuers were the highest users of other psychotropics and discontinuers were the lowest users compared to other groups (26%).

Conclusions: Most pregnant women with ADHD discontinue or interrupt their medication during pregnancy. However, more are choosing to continue use throughout pregnancy in recent years. Continuers are characterized by older age, less nulliparity and cohabitation, more smoking and higher use of other psychotropics. Family dynamics (having a child or partner) may play a role in treatment trajectories.