Treatment of Asymptomatic Bacterial Vaginosis
Asymptomatic BV generally does not require treatment in most women, but specific high-risk situations mandate therapy to prevent serious infectious complications. 1
General Approach to Asymptomatic BV
The primary goal of BV therapy is to relieve vaginal symptoms and signs of infection, which by definition are absent in asymptomatic cases. 2, 1 Approximately 50% of women with BV meeting clinical criteria have no symptoms. 1
Routine screening and treatment of asymptomatic BV in the general population is not recommended. 3
Specific Clinical Situations Requiring Treatment
Before Gynecologic Procedures
Treatment of asymptomatic BV is strongly indicated before surgical abortion to substantially reduce post-abortion pelvic inflammatory disease (PID). 2, 1 Two randomized controlled trials demonstrated that metronidazole treatment reduced postabortion PID by 10-75%. 2
Treatment should be considered before hysterectomy due to increased risk of postoperative infectious complications. 1 Seven trials evaluating anaerobic antimicrobial coverage before hysterectomy found substantial reduction (10-75%) in post-operative infections. 2
BV has been associated with endometritis, PID, and vaginal cuff cellulitis after invasive procedures including:
Pregnancy Considerations
High-risk pregnant women with a history of prior preterm delivery who have asymptomatic BV may be evaluated for treatment to potentially reduce risk of prematurity. 2, 1, 3 Several investigations indicate that treatment of pregnant women at high risk for preterm delivery may reduce the risk for prematurity. 2
However, routine screening and treatment of asymptomatic BV in all pregnant women (low-risk) is not recommended. 1 The 2020 US Preventative Task Force recommended against universal screening and treatment of asymptomatic BV in pregnant women. 4 A Cochrane review found that while antibiotics eradicate BV, treatment did not reduce the risk of preterm birth before 37 weeks in unselected populations (OR 0.91,95% CI 0.78-1.06). 5
There is some evidence that treatment before 20 weeks' gestation may reduce preterm birth risk (OR 0.63,95% CI 0.48-0.84), though this requires further verification. 5
Treatment Regimens When Indicated
First-Line Options
When treatment of asymptomatic BV is indicated, use the same regimens as for symptomatic disease:
- Metronidazole 500 mg orally twice daily for 7 days (95% cure rate, highest efficacy) 1, 6
- Metronidazole gel 0.75%, one full applicator (5g) intravaginally once daily for 5 days 1, 6
- Clindamycin cream 2%, one full applicator (5g) intravaginally at bedtime for 7 days 1, 6
Alternative Options
- Metronidazole 2g orally as a single dose (84% cure rate, lower efficacy but may improve compliance) 1, 6
- Clindamycin 300 mg orally twice daily for 7 days 1, 6
Pregnancy-Specific Regimens
For high-risk pregnant women requiring treatment:
- Metronidazole 250 mg orally three times daily for 7 days is recommended for systemic therapy to address possible subclinical upper tract infection 7
Important Clinical Precautions
Patients using metronidazole must avoid alcohol during treatment and for 24 hours afterward due to potential disulfiram-like reaction. 2, 1, 6
Clindamycin cream is oil-based and may weaken latex condoms and diaphragms. 1, 6
Routine treatment of male sex partners is not recommended as it has not been shown to reduce recurrence rates. 2, 1, 3
Follow-up visits are unnecessary if no symptoms develop. 1, 6
Clinical Pitfalls to Avoid
Some women with "asymptomatic" BV actually have symptoms but do not recognize them as abnormal or infectious. 4 Consider asking specifically about malodorous discharge, particularly after intercourse, as this may be present but not volunteered. 8
Do not treat asymptomatic BV outside the specific high-risk situations outlined above, as the benefits do not outweigh the risks of unnecessary antibiotic exposure. 3