Doctors have been telling pregnant women that Tylenol has been safe to take for years, but a new study conducted at the University of Edinburgh has turned this belief on its head. The study, published in Science Translation Medicine, found that prolonged use of acetaminophen (aka Tylenol) during pregnancy can reduce the testosterone of boys in utero by up to 45%.
While testosterone production remained normal after one day of Tylenol usage, after seven days it had dropped 45 percent. Some of the risks associated with low testosterone in males includes infertility, undescended testicles and testicular cancer. One of the researchers, Dr. Rob Mitchell states, "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."
He further claims that the "study adds to existing evidence that prolonged use of paracetamol in pregnancy may increase the risk of reproductive disorders in male babies."