A recent study published in Human Reproduction, Europe’s premier reproductive medicine journal, suggests that taking acetaminophen (Tylenol), aspirin, or ibuprofen (Advil) may raise the risk of undescended testicles in male babies, a condition linked to infertility and testis cancer in later life. Experts have been concerned for some time that chemicals that mothers may be exposed to during pregnancy could cause reproductive problems in male babies. Although it’s generally recommended for pregnant women to avoid medications during pregnancy, acetaminophen is considered by most OB/GYNs to be safe. Research has shown that over half of pregnant women in the U.S. use mild painkillers at some time in pregnancy, usually for headaches. Some of these drugs have been associated with anti‐androgenic effects in animal experiments. There may be a link between prenatal exposure to mild analgesics and reduced masculinization in animals.
It’s thought that some analgesics could act as endocrine hormone disruptors and lead to reduced masculization of a male fetus. This group of Danish investigators found that intrauterine exposure to mild analgesics is a risk factor for the development of male reproductive disorders in the human. Data was collected using questionnaires and telephone interviews of pregnant women along with careful examination of the position of the testes by pediatricians. The baby boys were examined at birth for any signs that the testes had failed to move into the scrotum before birth (cryptorchidism). Taking one painkiller doubled the risk overall, when compared to women who took nothing. Acetaminophen doubled the risk, while ibuprofen or aspirin increased it four‐fold. The results of study showed that women who used more than one painkiller simultaneously had a seven‐fold increased risk of giving birth to sons with some form of cryptorchidism compared with women who took nothing. Prolonged use of painkillers had the biggest effect.
In conclusion, exposure to mild analgesics in pregnancy may be a risk factor for development of male reproductive disorders. Although these finding are of great concern, further research is needed to draw firm conclusions about the effect of painkillers on male fertility. In the meantime, pregnant women, especially in the 2nd trimester, should limit their exposure to over the counter painkillers like ibuprofen and acetaminophen.