A new study shows that prolonged use of paracetamol may reduce testosterone production in unborn baby boys. Paracetamol is the primary medicine used for managing pain and fever during pregnancy.
"This study adds to existing evidence that prolonged use of paracetamol in pregnancy may increase the risk of reproductive disorders in male babies," said lead researcher Rod Mitchell, a clinical research fellow at the University of Edinburgh.
"We would advise that pregnant women should follow current guidance that the painkiller be taken at the lowest effective dose for the shortest possible time," Mitchell suggested.
The study tested the effect of paracetamol on testosterone production in mice that carried grafts of human testicular tissue.
These grafts have been shown to mimic how the developing testes grow and function during pregnancy.
Testosterone, produced in the testicles, is crucial for life-long male health. The mice were given a typical daily dose of paracetamol - over a period of either 24 hours or seven days. They measured the amount of testosterone produced by the human tissue an hour after the final dose of paracetamol. They found there was no effect on testosterone production following 24 hours of paracetamol treatment. After seven days of exposure, however, the amount of testosterone was reduced by 45 percent.
"Further research is required to establish the mechanism by which paracetamol might have this effect," the team concluded.
The study appeared in the journal Science Translational Medicine