Study links pregnancy paracetamol use to smaller testes and ovaries

A new study has linked mothers’ use of the painkiller paracetamol during pregnancy to smaller testes in boys and smaller ovaries in girls, DR reports. Researchers from the Department of Growth and Reproduction at Rigshospitalet say the findings are concerning.

The study followed 589 mothers who recorded their medication use during pregnancy. Their children underwent detailed examinations, including ultrasound scans of their ovaries or testes at three months of age.

Boys whose mothers had taken paracetamol had testes that were, on average, 8 per cent smaller than those of boys whose mothers had not taken the medicine. Girls had ovaries that were, on average, 41 per cent smaller, as well as fewer eggs and a smaller uterus.

Gylli Mola, a doctor and PhD student who led the part of the research involving boys, said the concerning point was that the women had taken only one or two days of the recommended maximum dose during pregnancy.

“It is remarkable that we see an association despite such a small dose,” she told DR.

Casper Hagen, a senior doctor and research leader on the study, said the findings suggested that paracetamol use during pregnancy might disrupt foetal development in ways that could still be detected long after birth.

However, the researchers stressed that their study was observational and could not establish that paracetamol directly caused the differences. The study also did not examine what the differences might mean for the individual children’s fertility later in life.

Paracetamol remains recommended for severe symptoms

Mola stressed that paracetamol remains the recommended medicine for pain during pregnancy.

“This is important not to interpret as a scare campaign,” she said. “If you have a high fever or severe pain, you should still take paracetamol.”

The findings are consistent with several independent animal studies suggesting that paracetamol can affect the development of ovaries and testes in foetuses.

Mola said the results could help pregnant women make more informed choices, particularly when pain relief was not essential. Most women in the study and generally take paracetamol for headaches or mild muscle, joint, lower back or back pain, she said.

In such cases, women could consider alternatives such as taking a nap, going for a walk, drinking water, getting a massage or resting, Mola said.

She added that greater attention might also be needed to ensure pregnant women receive enough support to avoid having to take medicine when other solutions may be available.