Results of a study provide “convincing evidence,” researchers say, that douching increases the risk of sexually transmitted infections.

Among a group of sexually active adolescent girls, those who said they always practiced vaginal douching were nearly two times more likely to have a sexually transmitted infection (STI) than girls who said they never douched, the researchers found.

“Douching is a harmful activity because it disrupts the healthy vaginal microorganisms and enables STIs to take hold,” Dr. Sten H. Vermund of Vanderbilt University School of Medicine, Nashville, Tennessee, told Reuters Health.

“Overwhelming evidence from biomedical research suggests that douching is harmful for women’s health,” Vermund added.

He and his colleagues studied the douching habits over 3 years of 368 sexually active girls who were nearly 17 years old on average.

During follow-up assessments, 88 of the girls never reported douching. Compared with this group, as well as the girls who intermittently reported douching, the 50 girls who reported always douching had a shorter time to acquiring a sexually transmitted infection.

When the investigators allowed for other factors associated with STIs, including race and age, as well as HIV status and baseline sexual history, the risk for STI was nearly twofold greater for girls who always douched compared with those who never douched.

In the American Journal of Obstetrics and Gynecology, the investigators note that this study is the first to follow girls over time, and to ensure that douching practices preceded incident STIs. Previous studies that suggested douching as a risk factor for STIs could not determine if douching was practiced in response to the STI symptoms.

Vermund concludes, based on this study and others, that “adolescents and women should be discouraged from douching unless guided to do so by a doctor.”

SOURCE: American Journal of Obstetrics and Gynecology, January 2009.