Experts say that using paracetamol and other painkillers during pregnancy could be dangerous for baby boys as there is a risk of undescended testicles.
This condition is linked to cancer in later life and also infertility. Pregnant women are already advised to avoid painkillers to protect their unborn baby although the NHS say that taking the occasional painkiller for a headache shouldn't cause any harm.
Researchers from Denmark, Finland and France looked at over 2,000 pregnant women and their babies and found those women who used more than one painkiller at the same time, like paracetamol and ibuprofen, had more than 7 times the risk of giving birth to sons with some form of undescended testes, or cryptorchidism, compared to women who took nothing. The researchers think that painkillers upset the natural balance of male hormones in unborn baby boys.
The second trimester, which is between 14 and 27 weeks of pregnancy, seems to be the most risky as any use of painkillers during this stage of pregnancy was linked to more than double the risk of some form of undescended testes. Paracetamol on its own also appeared to raise the risk although not to the same degree.
Paracetamol and Ibuprofen Together Very Dangerous in Second Trimester
The most horrific statistic to us TheBabyWebsite is that simultaneous use of more than one painkiller, including paracetamol, during the second trimester increased the risk 16-fold! Taking painkillers for more than two weeks at a time whilst pregnant also raises the risk significantly.
Pregnant women will obviously be worried by this new research but they need to realise that only prolonged use has an effect, and most women in the study who used paracetamol did not have a baby boy with undescended testes. The researchers believe that advice to pregnant women on the use of painkillers should be reconsidered.
Dr Allan Pacey, senior lecturer in andrology at the University of Sheffield, said: "Scientists have been concerned for some time about chemicals that the mother may be exposed to during pregnancy having the potential to cause reproductive problems in male babies". He called for more research and he said that he found ".......these studies somewhat alarming as I doubt that anyone would have suspected that common painkillers would have these effects."
Cryptorchidism affects around one in 20 boys in the UK.