MONDAY, Sept. 21, 2026 (HealthDay News) -- Prenatal exposure to acetaminophen is associated with differences in markers of ovarian development, according to a study published online Sept. 8 in Human Reproduction Open.
Margit B. Fischer, M.D., from Rigshospitalet in Copenhagen, Denmark, and colleagues conducted a single-center, prospective, observational cohort study involving 685 healthy singleton pregnant women and their 302 infant daughters to examine whether fetal exposure to acetaminophen is associated with markers of ovarian function in infancy. Acetaminophen exposure was classified according to timing: early fetal life (<17 weeks; 92 girls), mid-late fetal life (≥17 weeks; 67 girls), and unexposed controls (143 girls). A total of 1,210 girls were followed from infancy to adolescence in an independent confirmatory cohort.
The researchers observed an association for early fetal exposure with reduced ovarian volume and reduced uterine volume (−0.11 and −0.18 cm3); mid-late fetal exposure was associated with fewer ovarian follicles (−1.05 follicles) compared with no exposure. In girls exposed exclusively in early fetal life, anti-Mullerian hormone levels were lower compared with unexposed girls (−0.45 standard deviation scores). There was an inverse association seen for maternal urinary acetaminophen concentrations with ovarian and uterine volume and with breast tissue diameter. Fetal acetaminophen exposure was associated with reduced uterine volume at puberty in the independent confirmatory cohort (−4.11 cm3) and with smaller ovarian volume during adolescence (−2.76 cm3).
"Our findings should not discourage women from using paracetamol [acetaminophen] when it is medically indicated but rather encourage informed discussions about when medication is necessary and when alternative approaches may be considered," Fischer said in a statement.
