Using painkillers such as ibuprofen, aspirin and paracetamol in pregnancy may harm development of the sex organs in unborn boys, warn researchers.
They blame prolonged use of painkillers – two weeks or more – for contributing to an increased risk in boys born with undescended testicles.
Around half of women take over-the-counter painkillers during pregnancy, usually for headaches.
A new study shows women who used more than one type of painkiller simultaneously, for example ibuprofen and paracetamol, had a seven-fold increase in giving birth to sons with some form of problem with the testes.
It found the most vulnerable stage of pregnancy is four to six months when painkillers doubled the risk compared to women who took nothing.
Using ibuprofen and aspirin during the second trimester of pregnancy increased the risk four-fold, with a doubling of the risk for paracetamol.
Simultaneous use of two painkiller during this time increased the risk 16-fold, says the study, published in Europe’s leading reproductive medicine journal Human Reproduction today.
These disorders can lead to poor sperm quality and testicular cancer in later life, warn researchers from Denmark, Finland and France.
They claim painkillers may be behind the increase in male reproductive disorders in recent decades, along with exposure in the womb to chemicals in the environment known as endocrine or hormone disruptors.