Prenatal Tylenol Use Linked to Smaller Ovaries and Hormone Changes in Infant Girls, Study Finds
A Danish study reports that girls whose mothers took paracetamol during pregnancy had smaller ovaries, fewer follicles and altered hormone levels in early infancy.
Researchers from Copenhagen Analgesic (COPANA) examined 685 Danish women in their first trimester and later assessed 302 of their healthy daughters at three months old. Girls whose mothers reported or had measurable paracetamol in urine showed smaller ovaries, fewer ovarian follicles, altered reproductive hormone profiles and reduced uterine dimensions compared with unexposed peers. The study’s co-author Dr. Margit Bistrup Fischer said the results do not prove causation and that paracetamol remains important for treating fever or severe pain during pregnancy.
Nonetheless, the data contribute to an emerging signal that prenatal acetaminophen exposure may affect early reproductive development, a point echoed by the American College of Obstetricians and Gynecologists, which noted the clinical significance is still unknown. The authors call for larger, longer-term studies to determine whether these early differences translate into later fertility or reproductive-lifespan effects. The research joins earlier animal work and prior FDA warnings about potential neurodevelopmental risks of acetaminophen use in pregnancy.
Why it matters
It highlights possible risks of a common over-the-counter drug for fetal reproductive development, prompting caution and further study.
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