Bacterial vaginosis (BV) is a common vaginal condition caused by an imbalance in the bacteria that normally live in the vagina. It is not currently classified as a typical sexually transmitted infection (STI), but sexual activity can play an important role in developing or recurring BV.
Is BV an STI?
Not in the same way as chlamydia, gonorrhea, or trichomoniasis. ACOG describes BV as a bacterial imbalance rather than a true infection. However, recent research shows that BV-associated bacteria can be shared between sexual partners, and treating partners can reduce recurrence in some situations.
Common Symptoms
Many people with BV have no symptoms. When symptoms occur, they may include:
- Thin gray, white, or greenish vaginal discharge
- A strong fishy odor, often more noticeable after sex or during menstruation
- Occasional irritation or burning
Itching is not always prominent, and symptoms can overlap with yeast infection or an STI. Testing is often needed to know the cause.
How Is BV Treated?
BV is usually treated with prescription antibiotics such as metronidazole or clindamycin. The exact medicine, route, and duration depend on the individual situation.
Do not use leftover antibiotics or self-treat recurrent vaginal symptoms repeatedly without testing, because other conditions can look similar.
What About Treating a Sexual Partner?
ACOG updated its guidance in 2025. For some adults with recurrent, symptomatic BV, concurrent treatment of a sexual partner may be considered to reduce recurrence. ACOG specifically recommends considering oral plus topical antimicrobial treatment for male partners in selected cases and shared decision-making for other partner situations.
This does not mean every partner automatically needs treatment. The decision should be made with a clinician based on recurrence, symptoms, partner type, and current guidance.
BV During Pregnancy
BV during pregnancy can be associated with complications such as preterm birth in some patients. Because yeast infection during pregnancy can cause overlapping symptoms, pregnant people with vaginal symptoms should be evaluated and treated according to pregnancy-specific guidance rather than relying on self-diagnosis, over-the-counter products, or home remedies.
Can BV Be Prevented?
BV cannot always be prevented. Avoiding douching and using condoms consistently may reduce risk for some people. Recurrence is common even after appropriate treatment, so recurrence does not mean someone did anything wrong.
When to Get Medical Advice
Seek care for new vaginal discharge with strong odor, pelvic pain, fever, bleeding, sores, pregnancy, recurrent symptoms, or concern about an STI. Testing can distinguish BV from yeast infection, trichomoniasis, and other causes.
Bottom Line
BV is not currently considered a classic STI, but sexual transmission of BV-associated bacteria appears to contribute to recurrence. Newer ACOG guidance supports partner treatment in selected recurrent cases. Diagnosis and treatment should be individualized rather than based on headlines alone.
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Last reviewed for medical accuracy: September 2026.