Surprisingly, most Americans—84 percent of women and 66 percent of men—groom their pubic hair in some way, whether it’s trimming, waxing, shaving, or some combination thereof. All that hair removal can leave the area more exposed and irritated than it would be if left ungroomed, and researchers have wondered whether these practices might be tied to an increased risk of sexually transmitted infections (STIs).

To find out, a team of scientists surveyed 7,580 U.S. residents, ages 18 to 65, and asked them a slew of personal questions about their pubic-hair grooming habits, sexual activity, and STI status. The results, published on December 5 in the journal BMJ Sexually Transmitted Infections, show that people who groom are indeed more likely to contract an STI.

The association was clearest for STIs that have symptoms that appear on the skin, such as herpes, human papillomavirus (HPV), and syphilis. Compared to people who didn’t groom at all, those who removed all their pubic hair (via a Brazilian wax or similar procedure) at least once a month were four and a half times more likely to have an STI. Those who removed any amount of hair—even just a bit of trimming—at least weekly were three and a half times more likely to have an STI.

“It is absolutely possible that if people are grooming and creating nicks and tears, that creates more pathways to the bloodstream and puts them more at risk for infections like chlamydia," said Debra Herbenick, the director of the Center for Sexual Health Promotion at the University of Indiana–Bloomington (who was not involved in the study).

But the research doesn't address whether those who groom themselves down below are also more likely to engage in risky sexual behavior, Herbenick points out, so it's still unclear whether the practice of grooming is problematic.  

More research needs to be done, but in the meantime, if the study results worry you, reducing the amount or frequency of grooming—and avoiding sexual activity right afterwards—could help mitigate any risk. And whether you groom or not, the surest way to reduce your risk of getting an STI is to use a condom.

The Centers for Disease Control and Prevention also advises that people between the ages of 11 and 26 talk to their doctor about protecting themselves from HPV, which can cause genital warts or cervical cancer, by getting the HPV vaccine.