Acetaminophen Use During Pregnancy Linked to Risk of ADHD, ASD, Hyperactivity

Ilan Matok, PhD

Acetaminophen use during pregnancy has been linked to an increased risk of attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and hyperactivity symptoms.

Prolonged exposure to the over the counter medicine was associated with a 30% increase in the relative risk of ADHD and a 20% increase in the relative risk of ASD, compared to those that were not exposed to acetaminophen during pregnancy.

In a systematic review of data from the MEDLINE, EMBASE, and Cochrane databases up until January 2017, including 132,738 mother and child pairs (follow up 3-11 years), researchers found that the pooled risk ratio (RR) for ADHD was 1.32 (95% CI, 1.18 to 1.45; I² = 61%), for ASD was 1.23 (95% CI, 1.13 to 1.32; I² = 17%), and for hyperactivity symptoms was 1.23 (95%, 1.01 to 1.49; I² = 94%).

“Our study provides the first comprehensive overview of developmental outcomes following prolonged acetaminophen use during pregnancy,” Ilan Matok, PhD, the head of the Pharmacoepidemiology Research Lab at the Institute for Drug Research, in the Hebrew University School of Pharmacy, said in a statement. “Our findings suggest an association between prolonged acetaminophen use and an increase in the risk of autism and ADHD. However, the observed increase in risk was small, and the existing studies have significant limitations.”

“While [the] unnecessary use of any medication should be avoided in pregnancy, we believe our findings should not alter current practice and women should not avoid [the] use of short-term acetaminophen when clinically needed,” Matok added.

After a meta-regression analysis of the data, the association between the exposure to acetaminophen and ADHD increased as the child aged during follow-up and with the average duration of exposure (β = .0354, 95% CI, 0.001 to 0.07), (β = .006; 95% CI, 0.009 to 0.01).

The authors noted that while “these findings are concerning…results should be interpreted with caution as the available evidence consists of observational studies and susceptible to several potential sources of bias.”

When authors warned that the study data had limitations, they also noted that understanding pain and fever during pregnancy is imperative, as it can have a detrimental effect on the development of the fetus, thus pregnant women should still take acetaminophen for a short time in case of pain/fever

The study, “Prenatal Exposure to Acetaminophen and Risk for Attention Deficit Hyperactivity Disorder and Autistic Spectrum Disorder: A Systematic Review, Meta-Analysis, and Meta-Regression Analysis of Cohort Studies,” was published in the American Journal of Epidemiology.