Bacterial Vaginosis (BV) is a common, often frustrating condition that affects many people who have a vagina. When BV recurs shortly after successful treatment, it is easy to assume the sexual partner is the source of re-infection. This article clarifies the relationship between BV, its recurrence, and sexual activity, addressing the misconception that the partner is necessarily transmitting a foreign infection. Understanding the underlying biology and the current medical perspective on partner treatment can help individuals manage this persistent issue.
Understanding Bacterial Vaginosis
Bacterial vaginosis is defined as a disruption of the normal, healthy vaginal environment. The healthy vagina maintains an acidic state due to high numbers of beneficial Lactobacillus species bacteria. When BV develops, these protective lactobacilli are replaced by an overgrowth of other bacteria, such as Gardnerella vaginalis and Atopobium vaginae. This shift creates a polymicrobial environment and raises the vaginal pH level. BV is not classified as a traditional sexually transmitted infection (STI), as it is an imbalance of bacteria already present in the vagina. However, BV is strongly associated with sexual activity, and recurrence is common, affecting up to 50% of people within a year of initial treatment.
The Influence of Sexual Activity on Recurrence
Sexual activity, particularly unprotected intercourse, is a significant risk factor for BV recurrence because it can directly alter the vaginal environment. The acidic pH of a healthy vagina, typically between 3.8 and 4.5, acts as a natural defense mechanism against the overgrowth of BV-associated bacteria. Semen is alkaline, generally ranging from pH 7.2 to 8.0, and its introduction temporarily raises the vaginal pH. This temporary change creates a favorable environment for the BV-associated bacteria to proliferate, triggering a recurrence shortly after intercourse. The physical act of sex can also introduce or redistribute bacteria from the external genitals or the partner’s body into the vagina. This microbial exchange, coupled with the pH shift, disrupts the established flora and encourages the growth of the bacteria responsible for BV. Consistent use of barrier methods, like condoms, helps prevent this pH change by blocking the entry of alkaline semen.
Clarifying Partner Treatment Protocols
For many years, the standard medical consensus held that routine treatment of male partners was unnecessary to prevent BV recurrence. This stance was based on studies that found no significant benefit in treating male partners with antibiotics. The bacteria that cause BV do not typically colonize the male urethra or penis in a way that causes re-infection. However, recent research suggests this protocol may be evolving, particularly in cases of persistent recurrence.
A recent randomized controlled trial showed that concurrently treating male partners with a combination of oral and topical antibiotics, alongside the female partner’s standard BV treatment, significantly reduced recurrence rates. Recurrence dropped from 63% in the control group to 35% in the partner-treated group. This finding suggests that BV-associated bacteria can be exchanged during sex and that treating the partner may be an effective strategy for managing persistent BV.
While promising, the Centers for Disease Control and Prevention (CDC) guidelines have not yet fully incorporated routine male partner treatment. The successful trial protocol involved metronidazole tablets and a clindamycin cream applied topically to the penis for seven days. For female partners in same-sex relationships, a high concordance for BV is often reported, and some clinicians may recommend testing and treatment for the partner.
Strategies for Reducing Recurrence Related to Intimacy
To address the link between sexual activity and BV recurrence, several practical steps can be taken.
Barrier Methods and Hygiene
Consistently using barrier methods, such as condoms, during vaginal intercourse is highly effective. Condoms prevent the introduction of alkaline semen, which helps maintain the vagina’s natural acidic balance. Immediately after intercourse, gently rinse the external genital area with plain warm water and urinate. Avoid douching, scented soaps, or harsh cleansers in the vaginal area, as these disrupt the delicate microbiome and increase recurrence risk.
Post-Treatment Care
It is recommended to abstain from sexual activity during antibiotic treatment for BV and for a short time afterward. This allows the vaginal flora to fully re-establish. Some healthcare providers may also suggest using a short course of a vaginal probiotic or boric acid suppositories after intercourse. These can help stabilize the vaginal pH and reintroduce beneficial bacteria.