Tylenol use in pregnancy may be linked with uterus, ovary changes in daughters

Key Points:

• A study led by Margit Bistrup Fischer found that prenatal exposure to Tylenol (acetaminophen) may be linked to smaller ovaries, fewer ovarian follicles, smaller uteruses, and lower reproductive hormone levels in three-month-old baby girls, though it does not prove causation or predict future fertility outcomes.
• The study involved 302 infants categorized by timing of Tylenol exposure during pregnancy, with results showing a 40% smaller ovarian volume, 13% smaller uterine volume, and 23% fewer ovarian follicles in exposed infants, especially those exposed before 17 weeks gestation.
• Researchers emphasized that current guidelines still consider Tylenol safe for use during pregnancy and warned that untreated pain and fever also pose risks, urging no alarm among pregnant women who have used the drug.
• A separate larger cohort study found similar trends of smaller reproductive organs in girls exposed to Tylenol in utero during puberty and adolescence, indicating potential long-term effects that require extended follow-up into menopause.
• Experts suggest the findings align with animal research and recommend reassessing Tylenol use during pregnancy while continuing long-term monitoring of exposed individuals to clarify implications for reproductive health.