Prevalence and Temporal Trends of Attention Deficit Hyperactivity Disorder Medication Fills During Pregnancy and Breastfeeding in Denmark

Background and Objectives: Females of reproductive age are increasingly using attention deficit hyperactivity disorder (ADHD) medication, but its use during pregnancy and breastfeeding is largely unknown. The aim of this study is to examine the prevalence of ADHD medication fills during pregnancy and breastfeeding, including characteristics of these females and cohort differences over time. Methods: We conducted a descriptive study using Danish nationwide registers. Within cohorts of pregnant and breastfeeding females, we calculated the prevalence of ADHD medication (methylphenidate, amphetamine, dexamfetamine, lisdexamfetamine, modafinil, atomoxetine, clonidine and guanfacine) fills and described sociodemographic and clinical characteristics across groups with fills, no fills and previous fills. Cohort differences in ADHD medication fills during pregnancy for 2005–2010, 2011–2016 and 2017–2022 were examined. Results: In this cohort of 1,077,279 pregnancies, ADHD medication fills increased from 0.08 to 7.71 per 1000 individuals between 2005 and 2022. Among 446,485 breastfeeding females, fills increased from 0.55 to 3.67 per 1000 individuals from 2012 to 2022. Compared with the group with no fills, females filling ADHD medication during pregnancy and breastfeeding were younger, had lower levels of education, were more often smoking during pregnancy, utilised more psychiatric healthcare and had concurrent fills of other psychotropic medication. Cohort differences over time revealed that females filling ADHD medication during pregnancy in 2017–2022 were older, had higher levels of education, smoked less during pregnancy, had fewer psychiatric contacts and were less likely to fill other psychotropic medications compared with females in the earlier cohorts. Conclusions: Results showed an increasing prevalence of ADHD medication fills during pregnancy and breastfeeding in Denmark over time, surpassing the increase observed generally in females of reproductive age filling ADHD medication. Results revealed a difference in characteristics of females filling ADHD medication during pregnancy over time, suggesting a shift in pregnancy treatment patterns.