Bacterial Vaginosis: Patient Information
What is Bacterial Vaginosis?
Bacterial vaginosis (BV) is the most common vaginal infection in women of reproductive age, affecting approximately one-third of women in the United States. 1, 2 It occurs when the normal vaginal bacteria (primarily Lactobacillus species) are replaced by high concentrations of anaerobic bacteria including Gardnerella vaginalis, Prevotella, Mobiluncus, and Mycoplasma hominis. 3
Up to 50% of women with BV have no symptoms at all, but when symptoms occur, they typically include a thin, white or gray vaginal discharge with a characteristic fishy odor, especially after intercourse. 3, 2
Why Treatment Matters
Even if you have no symptoms, BV can lead to serious health problems including:
- Increased risk of preterm birth and premature rupture of membranes if you're pregnant 4, 3
- Higher risk of developing pelvic inflammatory disease 5, 1
- Increased susceptibility to sexually transmitted infections including HIV 5, 1
- Postoperative infections after gynecological procedures 5, 4
How is BV Diagnosed?
Your healthcare provider diagnoses BV when at least 3 of these 4 criteria are present (Amsel's criteria): 4, 3
- Thin, white, homogeneous discharge coating the vaginal walls
- Vaginal pH greater than 4.5
- Fishy odor when potassium hydroxide (KOH) is added to vaginal fluid (positive "whiff test")
- Clue cells visible under microscope
Newer molecular tests are also available that can provide more accurate diagnosis. 5
Treatment Options
The first-line treatment is metronidazole 500 mg taken by mouth twice daily for 7 days, which has a 95% cure rate. 4, 6 This is the most effective regimen recommended by the Centers for Disease Control and Prevention. 4
Alternative treatment options include: 4, 3
- Metronidazole gel 0.75% applied intravaginally once daily for 5 days
- Clindamycin cream 2% applied intravaginally at bedtime for 7 days
Critical Safety Information
You must completely avoid all alcohol during metronidazole treatment and for 24 hours after finishing the medication. 4, 3, 7 Combining alcohol with metronidazole can cause severe nausea, vomiting, flushing, and rapid heart rate (disulfiram-like reaction). 4, 6
If using clindamycin cream, be aware that it is oil-based and can weaken latex condoms and diaphragms, requiring alternative contraception during treatment. 4, 7
Special Situations
If You're Pregnant
All pregnant women with symptomatic BV should be treated, as BV is associated with preterm birth, premature rupture of membranes, and postpartum endometritis. 4, 3 Treatment with metronidazole has been shown to reduce these risks. 3
If you have a history of preterm delivery, your provider may recommend treatment even if you have no symptoms. 4, 7
Before Surgical Procedures
If you're scheduled for surgical abortion or hysterectomy, screening and treatment for BV is recommended because treatment substantially reduces post-procedure infections by 10-75%. 4
What About Your Partner?
Treatment of male sex partners is NOT recommended, as multiple studies show this does not prevent BV from coming back. 5, 4, 3 However, for women with frequent recurrences, some providers may consider partner treatment on a case-by-case basis. 7
Recurrence is Common
50-80% of women experience BV recurrence within one year after treatment. 1, 8 This high recurrence rate occurs because beneficial Lactobacillus bacteria often don't recolonize the vagina after antibiotic treatment. 1
- Extended metronidazole treatment for 10-14 days may be used
- Metronidazole gel twice weekly for 3-6 months as suppressive therapy can help prevent recurrence
- Any of the alternative treatment regimens can be tried
Follow-Up Care
You don't need a follow-up visit if your symptoms resolve. 4 However, if you're pregnant, a follow-up evaluation one month after completing treatment is recommended to confirm the infection is cured. 4, 7
Return to your healthcare provider if symptoms persist or come back after treatment. 7
Risk Factors and Prevention
BV is strongly associated with: 7
- Multiple sexual partners
- New sexual partners
- Frequent intercourse
- Douching
Women who have never been sexually active rarely develop BV. 7
Potential preventive measures include: 1
- Smoking cessation
- Condom use
- Avoiding douching