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RCOG statement: New study examining the effects of prolonged use of paracetamol during pregnancy

News 21 May 2015

A study published by the University of Edinburgh today (20 May) has suggested that prolonged paracetamol use by pregnant women may reduce testosterone in unborn baby boys.

The study tested the effect of a typical daily dose of paracetamol on testosterone production in mice. Results found no effect on testosterone production following 24 hours of paracetamol treatment. However, after seven days of exposure, the amount of testosterone was reduced by 45%.

The authors of the study recommend that expectant mothers should follow existing guidelines that the painkiller should be taken at the lowest effective dose for the shortest possible time.

Dr Sadaf Ghaem-Maghami, Chair of the RCOG Scientific Advisory Committee said:

“Paracetamol is one of the most common medicines used to reduce a high temperature and ease pain and is used routinely during all stages of pregnancy.

“This is a robust piece of research, however, it is important to note that the study was carried out in animal models and it is not possible to translate the findings into a recommendation regarding what would be safe or unsafe in pregnant women. Additionally, the mice were not pregnant but in a ‘pregnancy state’ which was induced by a hormone and human fetal testicular tissue which was grafted onto them.

“Further research needs to be conducted into how paracetamol may affect testosterone levels as well as examining the long term developmental effects on testosterone production.

“We recommend that pregnant women continue to follow current guidance and take the lowest effective dose for the shortest possible time when necessary. If the recommended dose of paracetamol doesn't control your symptoms or pain, please seek advice from your midwife, GP or obstetrician.”


For further information, please contact the RCOG Media and PR team on +44 20 7772 6300 or email