Pregnancy: Does Too Much Acetaminophen Heighten Risk for Autism or ADHD?

We’ve long been told that acetaminophen (Tylenol®, Paracetamol®) is the best pain reliever to take during pregnancy.

But studies suggest that taking the drug too often during pregnancy could increase your future child’s risks for developing autism or attention-deficit hyperactivity disorder (ADHD).

Ob/Gyn Salena Zanotti, MD, explains the risks and if using acetaminophen is safe.

What studies are saying

In a 2018 study, researchers did a meta-analysis of seven studies involving 132,738 pairs of mothers and children.

Mothers and children were followed for periods ranging from three to 11 years, depending on the study, using questionnaires, interviews, and self-reports on medication use. The analysis revealed a 20% higher risk of autism and a 30% higher risk of ADHD for children who had prolonged exposure to acetaminophen during fetal development.

However, it noted that taking small amounts of acetaminophen during pregnancy — in one study, for fewer than eight days — didn’t increase risks.

Other studies since then have supported earlier findings that too much acetaminophen may increase the risk for autism and ADHD in children.

“Acetaminophen is still the safest known drug to take during pregnancy for problems like fever and pain,” says Dr. Zanotti. “When you’re pregnant, it’s riskier to have an untreated fever than it is to take acetaminophen.”

Why autism and ADHD are on the rise

Experts are struggling to understand why autism is one of the fastest-growing developmental disorders in the United States, affecting 1 in every 44 8-year-old children.

The incidence of ADHD is also rising, affecting 9.4% of children ages 2 to 17.

“Both diseases likely stem from many different factors, so their true cause is poorly understood,” says Dr. Zanotti.

None of the studies reviewed looked at environmental factors, maternal characteristics or genetic factors, which could heighten the risk for autism or ADHD.

“We need more research to fully understand the effects of prolonged acetaminophen exposure on the baby during pregnancy,” she notes.

Is acetaminophen safe during pregnancy?

“If you have a fever or if pain is disrupting your daily life during pregnancy, it’s OK to take acetaminophen occasionally,” says Dr. Zanotti. “We just don’t want you taking acetaminophen everyday or long-term.”

Should you need pain relief while pregnant, discuss your options with your physician. For some conditions, limited amounts of acetaminophen might be your safest bet.