According to experts, pregnant women are at risk of giving birth to infertile sons if they take painkillers during pregnancy.

The scientists say the risk relates to prolonged use of drugs such as paracetamol, aspirin and ibuprofen, which they believe harms development of male reproductive organs.

The warning comes after research carried out in Copenhagen, Denmark by Henrik Leffers, senior scientist at Rigshospitalet. The research appears to show that mild painkillers operated as hormone disruptors, which in turn increased exposure to other chemicals found inside the womb.

Echoing this, Allan Pacey, who works at Sheffield University told reporters: “I doubt that anyone would have suspected that common painkillers would have these effects.”

Until now, GPs and others have advised pregnant women to avoid ingesting any drugs, but thought taking painkillers was O.K. It seems this research throws that advice out of the window now.

While the findings have been described by many as alarming, some have advised caution. Neal Patel of the Royal Pharmaceutical Society said: “This study adds to the body of evidence about the effect of medicines on foetal development. However, due to study limitations, further research is needed to draw firm conclusions about the effect of painkillers on male fertility.”

The findings from the research suggest women who ingested more than one type of painkiller simultaneously had a 7 fold risk of giving birth to an infertile boy.

The report also said that the most vulnerable stage was during the second trimester (4 – 6 months) of pregnancy. Taking one painkiller doubled the risk.

Unfortunately, for women who are currently pregnant this could be worrying news. As always, the medical profession maintain that they should consult their GP and other health care workers for advice.