Paracetamol exposure in the womb is linked to smaller wombs and altered ovaries in infant girls.
April 29, 2026
Original Paper
Fetal exposure to paracetamol is associated with altered markers of ovarian development and reduced uterine volume in girls: the COPANA study
medRxiv · 10.64898/2026.04.23.26351576
The Takeaway
Paracetamol is generally considered the safest painkiller for pregnant women, but new data suggests it may impact the reproductive future of their daughters. A study of infant girls found that those exposed to the drug before birth had significantly lower uterine volumes and markers of different ovarian development. These changes were visible shortly after birth, suggesting the drug interferes with the delicate window of fetal organ growth. While the long term effects on fertility are not yet known, the correlation is strong enough to warrant a re-evaluation of routine use. This discovery highlights a hidden risk in one of the world's most common medications. It forces a major rethink of what counts as a safe drug during pregnancy.
From the abstract
Study question; is fetal exposure to paracetamol associated with markers of ovarian function in infancy? Summary answer; Mild to moderate doses of prenatal paracetamol exposure, assessed by detailed maternal reports and urinary measurements, is associated with ovarian morphology and activity as well as reduced size of estrogen-responsive tissues in infant girls. What is known already; Maternal use of paracetamol is widespread. Across multiple independent animal studies, fetal exposure consistent