Bacterial Vaginosis

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#Bacterial vaginosis, uncomplicated
Amsel Criteria (≥3 of 4 required): Sensitivity 92%, specificity 77% vs. Gram stain
- Homogeneous, thin, white-gray discharge coating vaginal walls
- >20% clue cells on saline wet-mount microscopy
- Vaginal fluid pH >4.5
- Positive KOH whiff test (amine/fishy odor)

- Treatment: Metronidazole 500 mg PO BID for 7 days

Yellow *** markers = placeholders you fill in or delete per case.

Deep dive — rationale & evidence

Reference only — this section is not copied when you hit Copy. It explains the evidence behind the plan.

Treatment

Regimen	Dose	Duration	Notes
Metronidazole (oral)	500 mg PO BID	7 days	Recommended; safe in pregnancy (no teratogenicity)
Metronidazole gel 0.75%	1 applicator (5 g) intravaginally daily	5 days	Recommended alternative
Clindamycin cream 2%	1 applicator (5 g) intravaginally QHS	7 days	Recommended alternative
Clindamycin (oral)	300 mg PO BID	7 days	Alternative; ~85% cure rate in pregnancy
Clindamycin ovules	100 mg intravaginally QHS	3 days	Alternative; may weaken latex

•Avoid in pregnancy: tinidazole, secnidazole (insufficient safety data)
•Oral therapy is not superior to topical therapy for preventing adverse pregnancy outcomes
•Consider test of cure after treatment in pregnancy

Pregnancy-specific considerations

•BV is associated with preterm birth (OR ~1.76–2.19), PPROM (OR 2.59), and chorioamnionitis (OR 2.26), but treating asymptomatic BV does not reduce preterm delivery (RR 1.02, 95% CI 0.86–1.20) — the association appears to be a marker of underlying dysbiosis rather than a causal, modifiable driver.
•Therefore, screening asymptomatic pregnant women is NOT recommended regardless of preterm birth risk.

Sources

•ACOG Practice Bulletin No. 215 (2020) — Vaginitis in Nonpregnant Patients: Amsel criteria, treatment regimens, pregnancy safety
•CDC STI Treatment Guidelines — Workowski et al. (MMWR 2021) — Recommended BV treatment regimens and alternatives
•USPSTF Recommendation Statement — Owens et al. (JAMA 2020) — Screening for BV in pregnancy (Grade D for average risk; I statement for high risk)
•Kahwati et al. (JAMA 2020) — USPSTF systematic review on BV screening to prevent preterm delivery
•Cochrane Review — Brocklehurst et al. (2013) — Antibiotics for BV in pregnancy: treatment of asymptomatic BV does not reduce PTB (RR 1.02)
•Nugent et al. (J Clin Microbiol 1991) — Nugent scoring / Gram stain reference standard
•PREMEVA Trial — Subtil et al. (Lancet 2018) — Early clindamycin for BV in pregnancy; oral vs. topical equivalence
•Kenfack-Zanguim et al. (Eur J Obstet Gynecol Reprod Biol 2023) — Meta-analysis: BV association with PTB (OR 1.76–2.19), PPROM (OR 2.59)
•Paavonen & Brunham (NEJM 2018) — BV and desquamative inflammatory vaginitis overview
•Jayaram et al. (Eur J Obstet Gynecol Reprod Biol 2020) — BV in pregnancy review