Bacterial Vaginosis May Be Result of Sexual Intercourse - Everyday Health

Bacterial vaginosis (BV) is a common infection caused by a change in the bacterial balance in the vagina — and a treatable problem many women suffer from frequently. Now, a new study published in August 2020 in Frontiers in Cellular and Infection Microbiology suggests that her male partner may play a role in this.

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When the Penis Microbiome and the Vaginal Microbiome Meet

Researchers followed 168 heterosexual couples in which the women did not have bacterial vaginosis at the start of the study and assessed the presence of BV after one month, six months, and a year, using vaginal swabs; also, at each visit, the men had swabs taken of the bacteria in and around their penises (what's called the "penile microbiome"). Over the course of the year, 31 percent of the women developed BV. The incidence was slightly higher among women whose partners hadn't been circumcised, perhaps because the warm, moist space under the foreskin can harbor bacteria and allow them to grow.

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The Penile Microbiome and its Role in Women's BV

When the researchers considered the results of the men's swabs along with the women's, they found that the composition of a man's penile microbiome — namely, the presence of certain bacteria — could predict the development of BV in their female partners. "Bacteria that have been associated with BV in women have been recovered from the skin of the penis, the semen, and men's urine," explains study lead author Supriya Mehta, PhD, an associate professor of epidemiology and biostatistics at the University of Illinois Chicago School of Public Health. "Like many other bacteria, the exchange of penile and vaginal bacteria is most likely bidirectional."

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Sharing Microbes During Intimate Encounters

Simply put, a man's penis has a microbiome, just as a woman's vagina does, and during penetrative sex these communities of bacteria can interact with each other and impact each partner's reproductive health. It may be that BV-associated bacteria from some men's microbiomes can directly impact the onset of BV in women when they're transmitted to the vagina during intercourse or that the penile bacteria may disrupt the natural balance of vaginal bacteria in ways that could induce BV over time. More research needs to be done to tease out the exact mechanisms but this much is clear: BV is a his-and-hers proposition.

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Bacterial Vaginosis: Causes and Risk Factors

Indeed, the study findings may be a game changer in terms of understanding the possible causes of BV and perhaps the best ways to treat it. "Prior thought has been that the alkalinity of semen in the vagina produced this alteration in vaginal flora [that could lead to BV]," notes Michael Cackovic, MD, an ob-gyn at The Ohio State University Wexner Medical Center in Columbus. "What this study suggests is that the penile microbiome may be a cause of the disruption of the vaginal environment."

BV Can Be Treated; Problems May Occur When It Is Not

This new understanding is especially important because if left untreated BV can lead to pregnancy complications (such as having a low-birth-weight baby or premature rupture of the membranes), as well as increasing a woman's susceptibility to sexually transmitted diseases such as HIV, herpes, gonorrhea, and chlamydia.

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Bacterial Vaginosis Cases Tend to Come Back Often

What's more, BV has a high rate of recurrence — up to 58 percent of women have a recurrence over the course of a year after being treated with oral antibiotics, research published in the Journal of Infectious Disease found. (Symptoms of BV can include a white or gray vaginal mucus or discharge with a strong fishy odor and sometimes itching, according to the American College of Obstetricians and Gynecologists.)

"I would use this study to counsel those patients [who are] frustrated by recurrent bacterial vaginosis that this may be another reason causing the recurrence," Dr. Cackovic says.

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Would Treating a Woman's Male Sex Partner Help Prevent BV?

In fact, the study findings suggest that treating BV in both partners may be more effective in reducing recurrence rates than just treating the women. "Our next step is to design a randomized controlled trial to treat male sex partners with antibiotics to see if this can reduce BV recurrence in female sex partners," Dr. Mehta says. "We need to find out what amount, duration, and type of antibiotics are most effective, and if men are willing to take the medicine when they themselves do not have symptoms."

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Inclusion of Sex Partners and Holistic Healthcare

Another important take-home message, Mehta adds: "I would like for clinicians, researchers, and the public to be inclusive of male sex partners in their efforts to improve women's reproductive health."

Bacterial Vaginosis May Be Result of Sexual Intercourse - Everyday Health