What are the signs and symptoms of Bacterial Vaginosis (BV)?

Signs and Symptoms of Bacterial Vaginosis

Bacterial vaginosis presents with four cardinal features: homogeneous white vaginal discharge, fishy odor (especially after intercourse or menses), vaginal pH >4.5, and clue cells on microscopy—though approximately 50% of affected women remain completely asymptomatic. 1, 2

Clinical Presentation

Symptomatic Disease (50% of cases)

Vaginal discharge characteristics:

• Homogeneous, thin, white or gray discharge that smoothly coats the vaginal walls (not thick or clumpy) 1, 2
• Non-inflammatory in nature—the vaginal walls typically lack erythema or irritation 1

Characteristic odor:

• Fishy or musty vaginal odor, often described as amine-like 3, 4
• Odor becomes more pronounced after intercourse or during menstruation due to alkaline pH changes 2
• The "whiff test" (fishy odor immediately after applying 10% KOH to discharge) is positive 1, 2

Additional symptoms:

• Vaginal itching (less common than with candidiasis) 3
• Increased vaginal pH (>4.5) 1, 2

Asymptomatic Disease (50% of cases)

A critical clinical pitfall is that up to half of women meeting diagnostic criteria for BV report no noticeable symptoms whatsoever. 1, 2, 5 This asymptomatic presentation is particularly important because:

• These women remain at risk for serious complications including pelvic inflammatory disease, endometritis, and adverse pregnancy outcomes 2
• Asymptomatic BV increases susceptibility to sexually transmitted infections 2
• Women undergoing invasive gynecological procedures require screening even without symptoms 2

Diagnostic Findings on Examination

Microscopic findings:

• Clue cells (vaginal epithelial cells with adherent bacteria obscuring cell borders) on wet mount examination 1, 2
• Absence of inflammatory cells—this distinguishes BV from trichomoniasis 1
• Shift from normal Lactobacillus-dominant flora to mixed anaerobic bacteria on Gram stain 1, 2

Physical examination findings:

• Vaginal pH greater than 4.5 (normal is 3.8-4.5) 1, 2
• Absence of vulvar inflammation or erythema (helps differentiate from candidiasis) 1
• Discharge that is thin and adherent rather than thick and cottage cheese-like 2, 4

Key Clinical Distinctions

What BV is NOT:

• BV does not cause vulvar itching, burning, or significant irritation as the primary complaint (these suggest candidiasis) 4
• BV does not produce a profuse, yellow-green, frothy discharge (this suggests trichomoniasis) 4
• BV does not cause vulvar or vaginal erythema or inflammation 1
• BV does not cause painful intercourse as a primary symptom 4

Important Clinical Considerations

The absence of symptoms does not exclude BV diagnosis—objective diagnostic criteria must be applied in high-risk populations including pregnant women, women planning pregnancy, and those undergoing invasive procedures. 2, 6 Women who have never been sexually active are rarely affected, though BV is associated with multiple sexual partners 1, 2. The condition has a high recurrence rate of 50-80% within one year, so patients should be counseled about potential symptom return 2.