Anti-inflammatory medications have been known to be harmful to the developing fetus. Many pregnant women instead have used acetaminophen (Tylenol) for fever or pain relief. Recent research has shown an increase in the risk for attention-deficit/hyperactivity disorder (ADHD) in children from prenatal acetaminophen exposure. The question is whether this is due to acetaminophen exposure or parental ADHD.

To answer this question, researchers compared data from a Norwegian registry of approximately 113,000 children born between 1999-2009 (including 2246 with ADHD) with data on maternal and paternal ADHD symptoms, pre-pregnancy use of acetaminophen, and conditions for acetaminophen use. These were the results:

1. When mothers used acetaminophen for < 7 days during pregnancy, they had a slightly lower risk for ADHD in their children.

2. When mothers used acetaminophen for >7 days during pregnancy, they increased the risk for ADHD in offspring in a dose-dependant manner.

3. Pregnant mothers’ use of acetaminophen for >29 days more than doubled the risk for ADHD regardless of why women were taking this medication.

4. Maternal acetaminophen use before pregnancy was not associated with an increased risk of ADHD in offspring. Pre-pregnancy use was used as a control which strengthens the argument that acetaminophen exposure, not maternal ADHD symptoms explains the findings.

5. Paternal pre-conception use of acetaminophen for >29 days was also associated with a higher risk for ADHD in offspring!

I think the most surprising finding was that the father’s use of acetaminophen prior to conception increased the risk for ADHD in offspring. This medication may influence spermatogenesis (the process of sperm cell development).

This is another risk factor for developing ADHD. Women should limit their use of acetaminophen during pregnancy and find other ways to reduce pain. Mindfulness and yoga are a few ways to help tolerate the stress of parenting. ADHD is primarily determined by genetic factors so no woman should feel guilty about their prenatal acetaminophen use. I’m sure we will continue to find other risk factors as well as advances in treatment of this complex condition.

Ystrom, E et al. Prenatal exposure to acetaminophen and risk of ADHD. Pediatrics 2017 Nov; 140:e20163840.

Wolraich ML. An association between prenatal acetaminophen use and ADHD: The benefits of large data sets. Pediatrics 2017 Nov; 140e20172703.