Maternal Use of Acetaminophen Linked to ADHD in Kids

https://www.medscape.com/viewarticle/887773

A pregnant woman’s use of acetaminophen may be associated with an increase in her child’s risk for attention-deficit/hyperactivity disorder (ADHD), the authors of a large, prospective study report.

“[L]ong-term acetaminophen use during pregnancy is related to more than a twofold increase in risk for offspring ADHD,” after adjusting for genetic risk factors, indications for the mother’s acetaminophen use, use of the drug before pregnancy, and other potential confounders, lead author Eivind Ystrom, PhD, and colleagues write in an article published online today and in the November issue of Pediatrics.

Conversely, use of acetaminophen for less than 8 days during pregnancy was associated with a decrease in ADHD risk, suggesting its antipyretic effect “could be beneficial with regard to fetal development,” the authors add.

In an accompanying commentary, Mark L. Wolraich, MD, who was not involved in the study, cautions that these findings do not establish a causal relationship between prenatal acetaminophen exposure and ADHD risk, “but they do suggest the possibility and raise the need for further study and more cautious consideration of acetaminophen use during pregnancy.”

It is estimated that approximately 65% to 70% of pregnant women in the United States and approximately 50% to 60% of pregnant women in western and northern Europe use acetaminophen.

Data on More Than 100,000 Children

For the current study, Dr. Ystrom, from the Norwegian Institute of Public Health, Oslo, and colleagues analyzed data from the Norwegian Mother and Child Cohort Study, which includes information on 114,744 children born between 1999 and 2009, as well as on 95,242 mothers and 75,217 fathers throughout Norway.

Mothers and fathers alike completed questionnaires at 18 weeks of gestation. The mothers also filled out questionnaires later in pregnancy, after delivery, and when their children reached 6 months, 1.5 years, and 3 years of age. The researchers obtained information on ADHD diagnoses from records maintained by the Norwegian Patient Registry.

The parents’ questionnaires included questions about their acetaminophen use. To control for potential confounders, the mothers also answered questions regarding various medical conditions for which acetaminophen was indicated, as well as the duration of their acetaminophen use. Their children were followed to the time of their ADHD diagnosis or until December 31, 2014.

The final sample consisted of 112,973 children and their parents. Of those children, 2246 (2%) were diagnosed with ADHD, and 52,707 (46.7%) mothers reported some acetaminophen use during pregnancy. Compared with no acetaminophen exposure, the unadjusted hazard rate (HR) of ADHD in children after 1, 2, or 3 trimesters of prepartum exposure was 17%, 39%, and 46%, respectively.

Duration Makes a Difference

When the authors adjusted for parental ADHD symptoms, the risk associated with acetaminophen use declined slightly, from an HR of 1.26 in the unadjusted model to 1.20 (95% confidence interval [CI], 1.09 – 1.32). However, when calculated by amount of exposure, the rate rose from 1.13 (95% CI, 1.01 – 1.27) for any one trimester to 1.32 (95% CI, 1.16 – 1.50) for any 2 trimesters, and to 1.34 (95% CI, 1.05 – 1.71) for all three trimesters.

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