The Influence of Behaviors and Relationships on the Vaginal Microbiota of Women and Their Female Partners: the WOW Health Study

Background: A community-based study of women who have sex with women (WSW) was performed to determine the burden of bacterial vaginosis (BV), and behavioral factors influencing the vaginal microbiota of women and their female sexual partners (FSPs), as measured by Nugent score (NS).

Methods: In a cross-sectional study of 18-55-year-old WSW recruited nationally, participants completed questionnaires and self-collected vaginal swab samples weekly on 3 occasions. BV was defined as an NS of 7-10. Factors associated with BV, stability of NS category, and concordance of these categories in co-enrolled couples were examined with multivariable logistic regression analysis.

Results: A total of 458 participants were recruited; 192 were co-enrolled with their FSP (96 couples). BV was detected in 125 women (27%; 95% confidence interval [CI], 23%-32%). BV was associated with ≥4 lifetime FSPs (adjusted odds ratio [AOR], 1.9; 95% CI, 1.2-3.1), an FSP with BV symptoms (AOR, 2.9; 1.0-8.2) and smoking, with ≥30 cigarettes per week showing greatest odds (AOR, 2.7; 1.5-5.0). Of 428 women returning ≥2 swab samples, 375 (88%) had a stable NS category across all samples, predominantly reflecting normal flora. Co-enrolled WSW were less likely to have BV (31% vs 23%; P = .07), and the majority (70%) were concordant for NS category (κ = 0.47; P ≤ .01), with most concordant for normal flora. Concordant NS category was associated with a relationship of >6 months (AOR, 4.7; 95% CI, 1.4-16.4) and frequent sexual contact (more than once per month; AOR, 2.7; 1.0-7.1).

Conclusions: BV is associated with key behaviors and smoking practices in WSW, but longer-duration, sexually active WSW partnerships support a stable favorable vaginal microbiota.