http://www.webmd.com/women/news/20031219/yeast-infections-not-mens-fault

Dec. 19, 2003 -- Specific sex practices -- and not infection in men -- are linked to women's recurring yeast infections, a new study shows.

Those sex practices -- oral sex performed on a woman and masturbation with saliva -- don't actually spread yeast infections, researchers report. Instead, they may in some women create conditions that let yeast grow out of control.

University of Michigan researcher Barbara D. Reed, MD, MSPH, led the study of 148 women and 78 of their male sex partners.

"Many physicians -- and many women -- believe that women get recurrent yeast infections because their partner passes the yeast back to them during intercourse. This study refutes that belief," Reed says in a news release.

All of the women originally were treated for candidayeast infections. Reed's team collected culture samples from the women's tongue, feces, vulva, and vagina and from their sex partners' tongue, feces, urine, and semen.

The women had check-ups at two weeks, four weeks, six months, and a year -- as well as whenever they had a yeast infection. Whenever a woman had symptoms of a yeast infection, her sex partner was checked as well.

Yeast can live peacefully in the vagina without overgrowing and causing the intense itching and burning that indicate candida vulvovaginitis or yeast infection. Reed's team confirmed this. Women found to have yeast in their vaginas during follow-up visits were no more likely than other women to have recurring symptoms of yeast infection.

Detection of yeast in male sex partners had nothing to do with whether women had recurring yeast infections.

However, sex behaviors showed a strong connection. Cunnilingus -- oral sex performed on a woman -- tripled the women's risk of recurring yeast infections. And masturbation with saliva -- both by women and by their sex partners -- doubled women's risk of recurring yeast infection.

Reed and colleagues suggest that a delicate balance exists between yeast, normal vaginal bacteria, and vaginal immune mechanisms.

"We suggest that the effects of genital washing with saliva -- from either the male or the female -- might upset this balance," they write in the December issue of the Journal of Women's Health.

The study also showed two other things that increase a woman's risk of recurring yeast infections: Eating two or more servings of bread each day, and their male sex partners who first had sex at an early age. It's not yet entirely clear how these factors play a role in yeast infections.