BV stands for bacterial vaginosis, the most common vaginal infection in women of reproductive age. It happens when the balance of bacteria inside the vagina shifts, with protective bacteria declining and other types overgrowing. Globally, an estimated 23 to 29 percent of women of reproductive age have BV at any given time.
What Happens Inside the Vagina During BV
A healthy vagina is home to large numbers of beneficial bacteria that keep the environment slightly acidic, typically at a pH below 4.5. This acidity acts as a natural defense against harmful microbes. In BV, those protective bacteria lose their foothold, and a mix of other bacteria multiply rapidly. The vaginal pH rises above 4.5, creating an environment where these bacteria thrive and produce byproducts responsible for the condition’s hallmark symptoms.
BV is not a sexually transmitted infection, though sexual activity is one of several factors associated with it. It can affect anyone with a vagina, including people who have never been sexually active.
Common Symptoms
Many people with BV notice a thin, grayish-white or yellowish discharge that has a distinct fishy odor. The smell is often strongest after sex or during a period. The discharge tends to be uniform and milklike in consistency, coating the vaginal walls rather than appearing clumpy or thick.
That said, up to half of people with BV have no noticeable symptoms at all. The infection is frequently discovered during a routine exam. When symptoms do appear, they rarely include significant itching, burning, or redness. If those are your main complaints, a different type of infection (like a yeast infection) may be more likely.
Risk Factors and Triggers
Anything that disrupts the natural bacterial balance of the vagina can raise your chances of developing BV. The most well-established risk factors include:
- Douching: Rinsing the inside of the vagina washes away protective bacteria and is one of the strongest risk factors for BV.
- New or multiple sexual partners: Sexual activity can introduce new bacteria and shift the vaginal environment.
- Scented soaps or hygiene products: Fragranced washes, sprays, or wipes used in or around the vagina can irritate tissue and alter bacterial balance.
- Lack of condom use: Semen is alkaline and can temporarily raise vaginal pH.
BV is not caused by poor hygiene. In fact, overcleaning the vagina is more likely to trigger it than undercleaning.
How BV Is Diagnosed
Doctors typically diagnose BV using a simple in-office exam. The standard clinical method looks for at least three of four signs: a thin, homogeneous discharge; a vaginal pH above 4.5; a fishy odor when a chemical solution is applied to a sample of the discharge; and the presence of “clue cells” (vaginal cells coated in bacteria) under a microscope. The whole process takes just a few minutes and is not painful, though the swab can feel briefly uncomfortable.
Treatment and What to Expect
BV is treated with prescription antibiotics, typically taken orally twice daily for seven days or applied as a vaginal gel or cream. BV sometimes resolves on its own without treatment, but antibiotics significantly reduce the risk of complications.
Most people notice improvement within two to three days of starting treatment. It’s important to finish the full course even if symptoms disappear early, as stopping too soon increases the chance of the infection returning.
Why BV Keeps Coming Back
Recurrence is one of the most frustrating aspects of BV. More than 50 percent of people who are successfully treated experience a relapse within three to six months, and recurrence rates reach as high as 69 percent within a year. Researchers still don’t fully understand why some people are prone to repeated episodes, but it likely involves the protective bacteria failing to fully re-establish themselves after treatment.
If you deal with frequent recurrences, your doctor may recommend a longer or different course of treatment, or a maintenance regimen designed to keep BV from returning. Some people find that avoiding known triggers like douching and scented products helps reduce the frequency of flare-ups, though this doesn’t guarantee prevention.
Health Risks of Untreated BV
On its own, BV is not dangerous in most cases. But leaving it untreated over time does carry real risks. BV increases your susceptibility to sexually transmitted infections, including HIV, chlamydia, and gonorrhea. Those infections can in turn lead to pelvic inflammatory disease, a condition that can cause chronic pain and difficulty getting pregnant.
During pregnancy, BV raises the risk of preterm birth and low birth weight (under 5.5 pounds). Pregnant people with symptoms of BV are generally screened and treated to reduce these risks.
BV vs. Yeast Infections
BV and yeast infections are often confused because both involve vaginal discharge, but they feel quite different. Yeast infections produce thick, white, cottage cheese-like discharge and cause intense itching or burning. BV discharge is thinner, grayish, and accompanied by a fishy smell rather than itching. The treatments are also completely different: antifungals for yeast, antibiotics for BV. Using the wrong treatment won’t help and can make things worse, so getting the right diagnosis matters.