Risk of Gonococcal Infection During Vaginal Exposure is Associated With High Vaginal pH and Active Menstruation

An understanding of the biological reasons why 25% to 35% of women resist infection during vaginal intercourse with a man infected with Neisseria gonorrhoeae could lead to novel control measures. We sought modifiable biological bases for infection resistance by comparing women in the same core-mixing group who did or did not become infected after sexual exposure.

We enrolled 61 female contacts of index men with gonorrhea seen at Baltimore City Health Department clinics from January 2008 through May 2012. Exposure and sexual practices and histories, co-infections, physical signs on exam, patient symptom report, and menstrual history were collected.

Thirty-eight (62.3%) of the exposed women developed cervical infections. Multiple logistic regression found that a vaginal pH of 4.5 or higher at presentation to clinic was significantly associated with gonococcal infection (adjusted odds ratio, 5.5; P = 0.037) in women who presented within one menstrual cycle, 35 days. In this group of women, there was a significant association between acquiring an N. gonorrhoeae cervical infection and sexual exposure during menstruation (adjusted odds ratio 12.5; P = 0.05).

Modification of vaginal pH could be explored as novel strategy for reducing the risk of N. gonorrhoeae infections in women.