Side Effects of Painkillers During Pregnancy Linked to Reproductive Disorders

European researchers are warning that the use of common painkillers like Bayer Aspirin, Tylenol, Advil and Motrin during pregnancy may lead to reproductive disorders in male children.

According to the findings of the study, published Monday in the Human Reproduction medical journal, popular painkillers could be responsible for an increase in recent years in the number of boys born with undescended testicles; a condition known as cryptochidism. The reproductive disorder can lead to a reduction in the quality of semen and has been linked to an increased risk of testicular cancer.

The painkillers belong to a family of drugs known as nonsteroidal anti-inflammatory drugs (NSAIDs) and include Tylenol (acetaminophen), Bayer (aspirin), Advil (ibuprofen), Motrin (ibuprofen), and other popular painkillers; many of which are sold over-the-counter.

Millions of Americans, use these drugs for relief of mild pain and to reduce fevers. They are also commonly combined with other ingredients in many cold medicines.

About 2,800 pregnant Danish and Finnish women participated in two cohort studies, reporting to researchers when they used mild NSAIDs. Trained pediatricians then assessed the testicular position of their newborn male children.

The researchers found a dose-dependent link between the use of mild analgesics and Danish women in one cohort study. The risk was increased during the second trimester and when expecting mothers used different painkillers at the same time. The cohort study focusing on Finnish women did not generate the same results, however.

Researchers concluded that there was an association between the use of NSAIDs and the risk of cryptochidism. They said their findings in humans were backed up by impaired masculinization of rats in a similar experiment.