Bacterial Vaginosis (BV) is a common vaginal condition resulting from an imbalance of naturally occurring bacteria in the vagina. This microbial shift can lead to various symptoms, though some individuals experience no noticeable signs. Understanding BV’s biological mechanisms and risk factors is important for vaginal health.
The Core Mechanism: Bacterial Imbalance
The healthy vagina maintains a delicate balance of microorganisms, predominantly beneficial bacteria known as Lactobacillus species. These bacteria play a crucial role by producing lactic acid, which keeps the vaginal environment acidic, typically at a pH of around 3.8 to 4.5. This acidic environment inhibits the growth of other, potentially harmful, bacteria.
Bacterial vaginosis occurs when protective Lactobacillus species significantly decrease. As Lactobacillus levels decline, the vaginal pH rises, becoming less acidic. This change creates an environment where other bacteria, particularly anaerobic types, can overgrow.
Among the bacteria that proliferate in BV, Gardnerella vaginalis is frequently observed, though it is often present in healthy vaginas in smaller amounts. Other anaerobic bacteria like Prevotella, Mobiluncus, and Mycoplasma hominis are also found in increased concentrations. BV is characterized by a complex polymicrobial shift, where many bacterial species contribute to the imbalance.
Factors That Increase Risk
Several factors can disrupt the natural bacterial balance in the vagina, increasing the likelihood of developing BV. Sexual activity is a significant factor, with unprotected sex, new sexual partners, or multiple partners associated with higher risk. While the exact reason sexual activity influences vaginal bacteria is not fully understood, it can alter the vaginal environment.
Douching, the practice of washing out the vagina, is also linked to an increased risk of BV. It can flush away beneficial Lactobacillus bacteria and disrupt the vagina’s natural acidity, creating conditions favorable for anaerobic bacterial growth. Frequent douching can significantly increase the risk of developing BV.
Perfumed feminine hygiene products can also disturb the vaginal flora. These products may irritate vaginal tissues and alter the natural pH balance. Similarly, an intrauterine device (IUD) has been associated with an elevated risk of BV in some studies.
Common Misconceptions
Bacterial vaginosis is often misunderstood, leading to common misconceptions about its causes. BV is not considered a sexually transmitted infection (STI) in the traditional sense, as it results from an imbalance of bacteria normally present in the vagina, not solely through sexual contact. While sexual activity can increase the risk, individuals who have never had sex can still develop BV.
Another common misunderstanding is that poor hygiene causes BV. BV is not a result of uncleanliness; excessive cleaning practices like douching can contribute to its development.
BV is not caused by using tampons, wearing specific types of underwear, or being in hot tubs or swimming pools. The condition is an internal bacterial shift, not contracted from external surfaces or common hygiene products like tampons.