Prolonged use of paracetamol and other painkillers during pregnancy may pose a health risk to baby boys, warn experts.
Research suggests the drugs increase the risk of undescended testicles in male babies, a condition linked to infertility and cancer in later life.
Doctors already advise pregnant women to avoid taking painkillers if possible to protect their unborn child.
Experts said the Human Reproduction journal findings warranted further research "as a matter of priority".
But they reassured women that taking the occasional painkiller for a headache should not cause any harm.
Current advice from the NHS is that women should avoid taking medicines while pregnant but that paracetamol is considered safe if used in small doses for short-term pain relief.
Yet more than half of pregnant women in Europe and the US report taking mild painkillers.
In this latest investigation, researchers from Denmark, Finland and France studied more than 2,000 pregnant women and their babies.
They found those women who used more than one painkiller simultaneously, such as paracetamol and ibuprofen, had a seven-fold increased risk of giving birth to sons with some form of undescended testes, or cryptorchidism, compared to women who took nothing.
The second trimester - 14 to 27 weeks of pregnancy - appeared to be a particularly sensitive time.
BBC News
