Oral sex and BV transmission

It is true that some bacteria can be shared orally, and survive for certain periods of time in the mouth. This means that in theory, anyone who performs oral sex on a woman with bacterial vaginosis could get the infection in their mouth, and possibly even pass that infection on to other women – or other mouths.

There is enough evidence – though more research is certainly needed – to show that women with BV, and their partners, often have periodontal disease that reflects their vaginal dysbiosis. Yes, you can get BV in your mouth, and so can your partner.

The risk would be that a sexual partner would harbour BV-causing or -contributing bacteria in their mouths, and pass it to a vagina, which means they caught it off another vagina or penis, since penises can harbour BV bacteria and biofilms.

This is the case with, say, Helicobacter pylori, the bacteria that causes stomach ulcers. It has been found in genital tracts. We’re not sure what it does in there exactly, but its presence suggests it was passed by mouth to the genitals and may contribute to BV in some women.Read more about BV in the mouth. 

But lesbians have more BV and more oral sex!

Research is scant, but two studies have been done on lesbians that give us some clues, though mainly they tell us something we already knew: BV is sexually transmitted (not that BV is sexually transmitted by mouth specifically).

Lesbians have a higher incidence of BV (2.5-fold increased risk), but the link between oral sex and BV has yet to be properly studied and these studies do not detail oral sex specifically as a transmission route from a mouth infection and there is no evidence either way of BV-causing bacteria living in the mouth.

Women who have sex with women share vaginal fluids much more readily than male-to-female sexual partners – the more vaginas around, the more BV is going to appear. These bacteria tend to leave men’s bodies quickly without prolonged contact, but a penis can hang on to it for a while too.

Gardnerella vaginalis has been found in rare cases in some strange places on the body, but this is very uncommon and likely to be found in artificial joints and other areas with artificial implants.

References

1. Characterization of Vaginal Flora and Bacterial Vaginosis in Women Who Have Sex with Women, Jeanne M. Marrazzo Laura A. Koutsky David A. Eschenbach Kathy Agnew Kathleen Stine Sharon L. Hillier, The Journal of Infectious Diseases, Volume 185, Issue 9, 1 May 2002, Pages 1307–1313,
2. Evans AL, Scally AJ, Wellard SJ, et al, Prevalence of bacterial vaginosis in lesbians and heterosexual women in a community setting, Sexually Transmitted Infections 2007;83:470-475.