Menses Can Trigger Bacterial Vaginosis
Yes, menstruation can trigger bacterial vaginosis (BV) due to hormonal changes and alterations in the vaginal environment during menses. 1
Mechanism of Menses-Related BV Triggers
- Hormonal changes during menses lead to cervical alterations that may result in loss of the mechanical barrier preventing ascent of bacteria from the vagina to the upper genital tract 1
- The bacteriostatic effect of cervical mucus is lowest at the onset of menses, reducing protection against pathogenic bacteria 1
- Retrograde menstruation may favor ascent of bacteria to the fallopian tubes and peritoneum 1
- Marked increases in Gardnerella vaginalis (a key BV-associated organism) have been observed during menses 2
Vaginal Microbiome Changes During Menstruation
- During menstruation, quantities of protective Lactobacillus species (particularly L. jensenii and L. crispatus) decrease 2
- This decrease in Lactobacilli is inversely related to Gardnerella vaginalis concentrations, creating conditions favorable for BV development 2
- The healthy vagina is normally dominated by hydrogen peroxide-producing Lactobacillus species that protect against colonization by anaerobic bacteria 3
Clinical Implications
- BV is characterized by replacement of normal H₂O₂-producing Lactobacillus species with high concentrations of anaerobic bacteria, Gardnerella vaginalis, and Mycoplasma hominis 4
- BV is the most prevalent cause of vaginal discharge and malodor, with up to 50% of women with BV being asymptomatic 4
- Diagnosis requires three of the following Amsel criteria: homogeneous white discharge, presence of clue cells, vaginal pH >4.5, and fishy odor with KOH (whiff test) 4
Management Considerations
- Standard treatment for BV is metronidazole 500 mg orally twice daily for 7 days or clindamycin 4
- BV has high recurrence rates (50-80% within a year), which may be related to menstrual cycles 4
- For women with recurrent BV associated with menses, some clinicians consider prophylactic treatment before or during menstruation, though this is not part of standard guidelines 5
- Treatment of male sexual partners has not been shown to be beneficial in preventing recurrence of BV 4
Important Caveats
- While menses can trigger BV, other factors also contribute to BV development, including multiple sexual partners and alterations in vaginal flora 6
- BV increases the risk of contracting sexually transmitted infections and is associated with adverse pregnancy outcomes 6
- Women with prolonged dysbiosis (pH >5 or positive Amsel criteria) before symptomatic recurrence are more likely to experience recurrent BV 5
- Most BV recurrences happen within 10 days of menses, highlighting the temporal relationship between menstruation and BV 5