Use of ADHD medication during pregnancy from 1999 to 2010: a Danish register-based study

Abstract

Objective: This study aimed to describe the trends in use of Attention Deficit Hyperactivity Disorders (ADHD) medication during pregnancy in Denmark from 1999 to 2010, as well as to explore characteristics of women who use ADHD medication during pregnancy and whether exposure is associated with outcome of pregnancy.

Method: A linkage between various Danish national health registries was performed to identify all recorded pregnancies from 1999 to 2010. Use of ADHD medication was defined as a redeemed prescription on methylphenidate, modafinil, or atomoxetine from 28 days prior to the first day of the last menstrual period until the end of pregnancy.

Results: Of the 1 054 494 registered pregnancies, 480 were exposed to ADHD medication. From 2003 to the first quarter of 2010, use of ADHD medication during pregnancy increased from 5 to 533 per 100 000 person-years. A similar increase was observed among Danish women of childbearing age. Compared with unexposed, women who used ADHD medication during pregnancy were more often younger, single, lower educated, received social security benefits, and used other psychopharmaca. Exposed pregnancies were more likely to result in induced abortions on maternal request (odds ratio = 4.70, 95%CI = 3.77-5.85), induced abortions on special indication (odds ratio = 2.99, 95%CI = 1.34-6.67), and miscarriage (odds ratio = 2.07, 95%CI = 1.51-2.84) compared with unexposed pregnancies.

Conclusions: The number of pregnancies exposed to ADHD medication has increased similarly to the increase in use of ADHD medication among women of childbearing age. Use of ADHD medication in pregnancy was associated with different indicators of maternal disadvantage and with increased risk of induced abortion and miscarriage.

Keywords: ADHD; ADHD medication; attention deficit/hyperactivity disorder; pharmacoepidemiology; pregnancy; pregnancy outcome; psychostimulants.