Does Bacterial Vaginosis Cause Increased Vaginal Discharge?
Yes, bacterial vaginosis characteristically causes increased vaginal discharge—specifically a homogeneous, thin, white or grayish discharge that smoothly coats the vaginal walls. 1, 2
Characteristic Discharge Features
The discharge in BV has distinct qualities that differentiate it from other causes of vaginitis:
- Appearance: The discharge is homogeneous, thin, and milklike or white, coating the vaginal walls smoothly rather than appearing clumpy or thick 1, 3
- Color: Typically white or gray, distinctly different from the yellow-green frothy discharge of trichomoniasis or the thick white curdy discharge of candidiasis 2
- Odor: A fishy amine odor is present, particularly noticeable when the discharge is mixed with 10% KOH solution (positive whiff test) 1, 2, 4
- pH: The vaginal pH is elevated above 4.5, reflecting loss of protective lactobacilli 1, 2, 4
Clinical Significance
BV is the most prevalent cause of vaginal discharge and malodor in reproductive-aged women 1, 5. However, a critical caveat exists: up to 50% of women meeting diagnostic criteria for BV are completely asymptomatic, meaning they have no discharge or other symptoms despite meeting objective diagnostic criteria 1, 6.
Distinguishing BV from Other Causes
The absence of significant vulvar inflammation is a key distinguishing feature of BV 2. Unlike candidiasis or trichomoniasis, BV does not cause:
- Vulvar itching or irritation 2
- Vulvar erythema or edema 2
- Dyspareunia (though this can occur with aerobic vaginitis, a different condition) 7
The discharge characteristics help differentiate BV from other conditions: thin white discharge suggests BV, thick white curdy discharge suggests candidiasis, and frothy yellow-green discharge suggests trichomoniasis 2.
Diagnostic Confirmation
When increased discharge is present, BV diagnosis requires at least 3 of 4 Amsel criteria: homogeneous white discharge coating vaginal walls, clue cells on microscopy, vaginal pH >4.5, and positive whiff test 1, 4. The discharge alone is insufficient for diagnosis without these additional findings 1.