Trajectories of ADHD medication use before, during, and after pregnancy: A population-based study from Norway and Sweden.

PURPOSE: To describe ADHD medication use trajectories around pregnancy in Norway and Sweden. METHODS: We identified pregnancies resulting in births using linked data from birth and prescribed drug registers of Norway (2006-2019, N = 813 107) and Sweden (2007-2018, N = 1 269 146). We restricted to women who filled prescriptions for ADHD medication during pregnancy or in the year before or after. We described exposure as use versus no use, and total amount of drug dispensed in defined daily doses (DDDs). Group-based trajectory modeling was used to identify distinct medication use trajectories. RESULTS: In total, 13 286 women (0.64%) filled a prescription for ADHD medication. We identified four trajectory groups: continuers (5.7%), interrupters (23.8%), discontinuers (49.5%), and late initiators (21.0%). Discontinuers were younger, continuers were older on average. More women continued medication in recent years (2014-2019). Most discontinuers (60.7%) were nulliparous; more initiators and continuers had one or multiple previous births, respectively. Continuers were least likely to live with a partner (65.8%). Discontinuers were least likely (24.7%) and continuers most likely (37.6%) to smoke at the beginning of pregnancy. More continuers used amphetamine derivatives and were most likely to use other psychotropics. On modeling continuers, we identified three dose-trajectory groups which suggested that most women reduced medication dose during pregnancy. CONCLUSIONS: Most pregnant women discontinued or interrupted their ADHD medication during pregnancy, but more continued in recent years. Continuers were more likely to have had previous births, less likely to have lived with a partner, and may have had additional comorbidities warranting the use of other psychotropics.