February 24, 2014 — JAMA Pediatrics has published a study linking the use of Tylenol (acetaminophen) during pregnancy to an increased risk of having a baby with attention-deficit hyperactivity disorder (ADHD), or a related brain and behavior problem called hyperkinetic disorder (HKD).
In many countries, acetaminophen is the most widely-used pain and fever reducer during pregnancy. The study is concerning because many women have been told that Tylenol is safe to use during pregnancy.
Indeed, Tylenol is safer than ibuprofen and other NSAIDs (non-steroidal anti-inflammatory drugs), which can disrupt fetal development. However, researchers are concerned that Tylenol is a hormone disruptor. During pregnancy, abnormal hormone levels could harm fetal brain development.
The conclusions were based on data from 64,322 live births in Denmark between 1996 and 2002. Over 50% of pregnant women reported using acetaminophen. The exposed children were:
- 37% higher chance of being diagnosed with HKD
- 29% more likely to be prescribed ADHD medications
- 13% higher chance of ADHD-like behavior at 7 years old
The risk of ADHD-like behaviors and HKD were highest for babies exposed to acetaminophen for more than three months (one trimester) of pregnancy.
Although the study is troublesome, it does not prove cause-and-effect. Because acetaminophen is so widely-used during pregnancy, researchers are calling for more studies to investigate the pregnancy risks of Tylenol. While it may be a good idea to treat a fever with Tylenol during pregnancy, it is a good idea to be conservative when using it for minor headaches and pain.