Tylenol Use While Pregnant May Be Connected To Reproductive Changes In Young Girls, Study Suggests

Exposure to Tylenol’s active ingredient while in the womb may potentially impact reproductive organ development in young girls, according to a new study from across the Atlantic.

Copenhagen Analgesic’s (COPANA) study found that girls exposed to the drug paracetamol in utero had smaller ovaries, fewer ovarian follicles, differences in reproductive hormone levels and reduced uterine size during infancy.

The study enrolled 685 pregnant women in Denmark during the first trimester of pregnancy and examined 302 of their healthy infant girls when they were three months old.

Still, the researchers note that “whether these early-life differences have long-term clinical relevance, including effects on reproductive lifespan, remains uncertain” and requires further research with extended follow-up.

“Our study does not suggest that pregnant women should stop using paracetamol when it is genuinely needed, particularly for fever or significant pain,” study co-author Dr. Margit Bistrup Fischer told the Daily Caller News Foundation. “However, it does contribute to a growing signal that we should pay closer attention to use during pregnancy, especially because paracetamol is an over-the-counter medicine that is often perceived as entirely risk-free.”

The drug is known as acetaminophen in the U.S. Japan, and paracetamol in Denmark, the rest of Europe and most other countries. In addition to it being the primary active ingredient in Tylenol products, it is also among the most common active drugs nationwide, according to the company’s website.

“We hope this study will stimulate further research in this area as well as discussions among researchers, clinicians, and regulatory authorities,” Fischer continued. “While our findings add to a growing body of evidence, there is a need for larger studies with longer follow-up to determine whether the associations we observed with markers of female reproductive development and ovarian reserve translate into differences in reproductive health later in life.”

Researchers assessed paracetamol exposure using pregnant women’s reports of paracetamol use collected bi-weekly and by measuring paracetamol in their urine samples, according to the report.

Fischer also emphasized that any “women who have used paracetamol during pregnancy should not be alarmed” by the study’s findings.