This Study Just Linked A Chemical In Sunscreen To Birth Defects

You may remember the last time oxybenzone, a UV trapper used in 70 percent of sunscreen, was in the news: It was last summer, and Hawaii announced it would ban the compound by 2021 due to its toxicity to coral reefs. And now, new research has emerged on the oxybenzone's potential threat to humans too, particularly pregnant women.

According to a study published today in Reproductive Toxicology, it may increase the risk for a birth defect called Hirschsprung's disease (HSCR), a condition that affects the colon and leads to bowel obstruction in newborns. A rare disorder that requires surgery to treat, its underlying cause has stumped physicians for years. This is the first study to link it to oxybenzone exposure.

Researchers tested a group of 423 Chinese patients and their mothers; 101 had been diagnosed with HSCR, 103 required surgery for other digestive disorders, and 219 were otherwise healthy. Their data shows that there was a positive association between women who had medium to high levels of oxybenzone in urine and children who had HSCR.

This isn't the first time oxybenzone has been under fire in the health world: It's previously been linked to hormone disruption1 and increased risk of endometriosis2.

Since oxybenzone is small enough to pass through the skin and placenta barriers, the study's authors, and a handful of others in the medical community, are calling for pregnant women to avoid it altogether. 

"Oxybenzone and other soluble petroleum-based sunscreen filters permeate human skin and will contaminate even the unborn, representing a major exposure to hormone disrupters for all of us," Denis Dudley, M.D., an OB/GYN, said in response to the study. The authors of this study also advise women who are trying to get pregnant to avoid the chemical since it can stay in the body for weeks after exposure.