Treatment of Bacterial Vaginosis in Pregnant Women
For pregnant women with bacterial vaginosis, metronidazole 500 mg orally twice daily for 7 days or metronidazole 250 mg orally three times daily for 7 days is the recommended treatment, with the goal of reducing adverse pregnancy outcomes. 1
Diagnosis Confirmation
Before initiating treatment, confirm the diagnosis using clinical criteria (Amsel's criteria), which requires three of the following:
- Homogeneous, white, non-inflammatory discharge adhering to vaginal walls
- Presence of clue cells on microscopic examination
- Vaginal fluid pH greater than 4.5
- Fishy odor of vaginal discharge before or after addition of 10% KOH 1
Treatment Recommendations for Pregnant Women
First-line Treatment Options
- Metronidazole 500 mg orally twice daily for 7 days 1
- Metronidazole 250 mg orally three times daily for 7 days 1, 2
Alternative Treatment Option
- Clindamycin 300 mg orally twice daily for 7 days 1
Important Cautions and Contraindications
- Avoid metronidazole during the first trimester of pregnancy due to potential risks 1
- Avoid clindamycin cream during pregnancy due to increased risk of preterm birth 1
- Patients must avoid alcohol during metronidazole treatment and for 24 hours afterward to prevent disulfiram-like reactions 1
- Oral metronidazole commonly causes mild-to-moderate gastrointestinal disturbance and unpleasant taste 1
Treatment Based on Risk Status
High-Risk Pregnant Women (with history of previous preterm birth)
- Screening and treatment is recommended, preferably in the early second trimester 1
- Treatment may reduce the risk of preterm delivery in this population 1, 3
- Follow-up evaluation 1 month after treatment completion is recommended 1
Low-Risk Pregnant Women (without prior preterm birth)
- Treatment is recommended for symptomatic women 2
- Routine screening and treatment is not recommended for asymptomatic women at low risk 3
Follow-up and Management of Recurrence
- Follow-up evaluation 1 month after treatment completion is recommended for high-risk pregnant women 1
- Recurrence is common (50-80% of women experience recurrence within a year of treatment) 1
- For recurrent BV, use a different treatment regimen from the initial one 1
- Routine treatment of sex partners is not recommended, as clinical trials indicate that partner treatment does not affect a woman's response to therapy or likelihood of relapse/recurrence 1
Common Pitfalls to Avoid
- Using single-dose regimens, which have lower efficacy than the 7-day regimen 1
- Failing to warn patients about alcohol interaction with metronidazole 1
- Treating male sex partners, which has not been shown to improve outcomes or prevent recurrence 1, 2
- Using clindamycin cream or ovules with latex condoms or diaphragms, as they may weaken these products 1