Bacterial Vaginosis
Bacterial vaginosis (BV) is the most common vaginal infection in reproductive-age women. It results from an imbalance of vaginal bacteria and often causes a thin discharge with a fishy odor.
Table of Contents
Quick Facts
- ICD-10: N76.0
- Type: Bacterial imbalance, not strictly an STI
- Treatment: Antibiotics
- Recurs in: ~50% within 12 months
Symptoms
- Thin, gray-white discharge
- 'Fishy' vaginal odor, often worse after intercourse
- Sometimes mild itching or burning
- Many people have no symptoms
Causes
BV occurs when the normal lactobacilli of the vagina are replaced by other bacteria (Gardnerella, Prevotella, others). Factors that disturb the vaginal microbiome include:
- New or multiple sexual partners
- Douching
- Antibiotic use
- Hormonal changes
Diagnosis
- Examination of vaginal discharge
- Whiff test (odor with KOH)
- Microscopy (clue cells)
- pH testing (>4.5 in BV)
- Molecular tests
Treatment
- Metronidazole (oral or vaginal) — first-line
- Clindamycin (cream or oral) — alternative
- For recurrent BV: longer courses, vaginal boric acid, or other strategies
Prevention
- Avoid douching
- Use condoms consistently
- Limit number of sexual partners
- Avoid scented vaginal products
When to See a Doctor
See a doctor for any abnormal discharge, odor, itching, or pain. BV during pregnancy increases risk of preterm birth and should be treated.
Frequently Asked Questions
BV is not strictly classified as an STI but is associated with sexual activity. People who have not been sexually active can still develop BV.
About half of women have BV return within a year. Factors include reinfection from a partner, persistent biofilm bacteria, and underlying microbiome differences.
References
- Centers for Disease Control and Prevention. Bacterial Vaginosis — CDC STI Treatment Guidelines.