Girls whose mothers took acetaminophen during pregnancy had smaller ovaries, fewer ovarian follicles, and smaller uteruses at about 3 months of age than girls who were not exposed, according to a Danish study published September 8 in Human Reproduction Open. The study found an association, not proof that the medication caused the differences, and the lead author says it should not stop pregnant patients from using the drug when they need it.
That caveat matters. Acetaminophen, sold as Tylenol and known as paracetamol outside the United States, is the pain reliever and fever reducer most often recommended in pregnancy, and the study notes that more than half of pregnant women use it. Untreated fever can itself endanger the mother and fetus, and doctors caution that ibuprofen and aspirin can pose serious risks in pregnancy unless a clinician has recommended them.
