Can bacterial vaginosis (BV) cause vaginal bleeding?

Bacterial Vaginosis and Vaginal Bleeding

Bacterial vaginosis can cause vaginal bleeding, particularly in women with irregular bleeding episodes, and treatment with metronidazole can resolve these bleeding disturbances. 1

Understanding Bacterial Vaginosis

Bacterial vaginosis (BV) is a clinical syndrome resulting from replacement of the normal H₂O₂-producing Lactobacillus species in the vagina with high concentrations of anaerobic bacteria (e.g., Prevotella sp. and Mobiluncus sp.), Gardnerella vaginalis, and Mycoplasma hominis. 2

• BV is the most prevalent cause of vaginal discharge or malodor, though up to 50% of women with BV may be asymptomatic 2
• BV is associated with having multiple sexual partners, though it's unclear whether it results from acquisition of a sexually transmitted pathogen 2
• Women who have never been sexually active are rarely affected by BV 2

Diagnostic Criteria for BV

BV can be diagnosed using clinical criteria (Amsel criteria) requiring three of the following:

• A homogeneous, white, noninflammatory discharge that smoothly coats the vaginal walls 2
• The presence of clue cells on microscopic examination 2
• A pH of vaginal fluid greater than 4.5 2
• A fishy odor of vaginal discharge before or after addition of 10% KOH (the whiff test) 2

Alternatively, Gram stain can be used to determine the relative concentration of bacterial morphotypes characteristic of BV. 2

BV and Vaginal Bleeding

Research evidence supports a connection between BV and vaginal bleeding:

• A double-blind study found that women with BV can present with irregular bleeding episodes or discharge 1
• Treatment of BV with metronidazole resulted in resolution of all bleeding disturbances in affected patients 1
• The study demonstrated a 76% cure rate with metronidazole versus 5% with placebo, and repeated treatments resulted in a 100% cure rate 1

Complications Associated with BV

BV is not entirely benign and has been associated with several complications:

• Endometritis, pelvic inflammatory disease (PID), and vaginal cuff cellulitis after invasive procedures 2
• Adverse pregnancy outcomes including premature rupture of membranes, preterm labor, preterm birth, and postpartum endometritis 2, 3
• Increased susceptibility to sexually transmitted infections 4

Treatment Recommendations

The principal goal of therapy for BV is to relieve vaginal symptoms and signs of infection:

• All women who have symptomatic disease require treatment, regardless of pregnancy status 2
• Recommended treatment is metronidazole 500 mg orally twice daily for 7 days 5
• Alternative regimens include metronidazole gel 0.75% intravaginally once daily for 5 days or clindamycin cream 2% intravaginally at bedtime for 7 days 5
• For women with vaginal bleeding associated with BV, treatment with metronidazole has been shown to resolve bleeding disturbances 1

Important Clinical Considerations

• Treatment of male sex partners has not been shown to be beneficial in preventing the recurrence of BV 2, 4
• Patients using metronidazole should avoid alcohol during treatment and for 24 hours afterward due to potential disulfiram-like reaction 5
• Clindamycin cream is oil-based and might weaken latex condoms and diaphragms 5
• BV has a high recurrence rate (50-80% within a year), which may necessitate repeated treatments 4, 1

Clinical Pitfalls to Avoid

• Failing to consider BV in women presenting with vaginal bleeding, as it may be an underlying cause 1
• Not treating BV before invasive gynecological procedures, which may increase risk of post-procedure infections 2, 5
• Overlooking BV in pregnant women, as it is associated with adverse pregnancy outcomes 2, 3