Bacterial Vaginosis (BV) is a common condition resulting from a change in the natural balance of microorganisms that reside in the vagina. This shift is characterized by an overgrowth of various anaerobic bacteria, such as Gardnerella vaginalis, and a corresponding decrease in the protective Lactobacillus species. Lactobacillus bacteria normally produce lactic acid, which maintains the healthy, acidic environment of the vagina. When their numbers decline, the vaginal pH rises, creating a favorable environment for the overgrowing bacteria that cause BV. BV often leads to symptoms like a thin, grayish-white discharge and a distinct, sometimes “fishy” odor that may become stronger after intercourse. This article clarifies the nature of this imbalance and addresses the concern regarding its connection to infidelity.
Is Bacterial Vaginosis a Sexually Transmitted Infection?
Bacterial Vaginosis is not classified as a classic Sexually Transmitted Infection (STI), such as chlamydia or gonorrhea, because it is an imbalance of bacteria already present in the vagina, not an infection solely acquired from a partner. The condition is considered an endogenous event, meaning it originates from within the body. It is possible for a person who is not sexually active to develop BV, which fundamentally distinguishes it from true STIs. Therefore, a BV diagnosis does not automatically indicate infidelity.
The confusion arises because BV is significantly associated with sexual activity, particularly with a new partner or multiple partners. Researchers theorize that sexual activity can introduce new bacteria or alter the chemical environment of the vagina, such as by raising the pH temporarily, which triggers the overgrowth of the BV-associated bacteria. This association does not make it a sexually transmitted disease in the traditional sense, as the causative bacteria are not always foreign invaders. Unlike true STIs, treatment for a male sexual partner is typically not recommended, as it has not been shown to prevent recurrence.
BV can be passed between partners with vaginas, and in these cases, both individuals may need treatment if they are symptomatic. The exchange of vaginal fluids can facilitate the microbial shift. This highlights that while BV is linked to sex, it is primarily a disturbance of the microbial ecosystem.
Understanding the True Causes of Bacterial Vaginosis
The primary biological factor leading to BV is an increase in the vaginal pH, which results from the decline of the protective Lactobacillus bacteria. A healthy vagina typically maintains an acidic pH below 4.5, which inhibits the growth of harmful organisms. When this acidity is lost, the BV-associated bacteria, including various anaerobic species, thrive and form a complex structure called a biofilm. This biofilm allows the opportunistic bacteria to colonize the vaginal wall, making the infection difficult to eliminate.
Several common practices and conditions can disrupt this natural balance and increase the risk of developing BV. Douching is a significant risk factor because it flushes out the protective Lactobacillus bacteria and raises the vaginal pH, promoting the overgrowth of other bacteria. The use of scented products, such as fragranced soaps or feminine hygiene sprays, may also irritate the mucosal lining and alter the normal microflora. Hormonal fluctuations, such as those during menstruation or pregnancy, can also influence the vaginal environment and contribute to the risk of developing BV.
The introduction of new bacterial species during sexual activity is another factor that can trigger the imbalance. Semen has a naturally higher pH than the healthy vagina, and its presence can temporarily neutralize the protective acidity, which may be enough to allow the BV-associated bacteria to proliferate. Even with this link to sexual factors, the core issue remains the internal shift in the bacterial ecosystem, not the acquisition of a singular external pathogen.
Diagnosis and Management of BV
If symptoms like unusual discharge or odor are present, seeking a diagnosis from a healthcare provider is the appropriate next step. Diagnosis typically involves a pelvic examination and testing a sample of the vaginal discharge. The provider checks the vaginal pH, which is usually elevated above 4.5 in cases of BV. Microscopic examination can also reveal “clue cells,” which are vaginal cells heavily coated in the BV-causing bacteria, a definitive sign of the condition.
The standard management for BV involves prescription antibiotics, available in both oral and topical forms. Common regimens include metronidazole (oral pill or vaginal gel) and clindamycin (usually a vaginal cream). It is important to complete the entire course of medication as prescribed, even if symptoms improve quickly, to fully eradicate the overgrowing bacteria. Stopping treatment early increases the likelihood of recurrence.
Recurrence is a common challenge with BV, with many individuals experiencing symptoms again within a few months after initial treatment. For those with frequent recurrence, a healthcare provider may recommend an extended-use suppressive regimen. Timely treatment is advised, especially for pregnant individuals, as untreated BV can be linked to complications such as preterm birth.