The list of painkiller options for pregnant women just got even shorter.
Most moms-to-be are told to avoid aspirin and other nonsteroidal anti-inflammatory drugs like ibuprofen (the main ingredient in Advil and Motrin) and naproxen (found in Aleve). But now Tylenol, the most common recommendation for pain or fever during pregnancy, may also be unsafe, too.
Taking too much acetaminophen — the active ingredient in Tylenol — was found to reduce testosterone production in the womb in a new study. And this is bad news for male babies. Low testosterone in the womb can lead to infertility, testicular cancer, and hormone imbalances that make them prone to conditions like obesity and heart disease.
In the study, which was published in Science Translational Medicine, researchers tested mice with grafts of human tissue by exposing them to the drug. And they found that one day of exposure had no impact on the mice's testosterone production, while seven days of exposure reduced the amount of testosterone by 45%.
So does this mean pregnant women shouldn't take Tylenol at all? One of the study's authors, University of Edinburgh researcher Rod Mitchell, said taking the drug at current recommended doses should still be safe — for "the shortest possible time." And according to a prior study of thousands of women published by the National Institutes of Health, it's okay to take acetaminophen during all stages of pregnancy. Still, your safest bet may be a cold compress.