Reproductive tract infections are hypothesized to influence uterine fibroid development, yet few studies have investigated the common condition of bacterial vaginosis (BV). Literature is currently limited to data using self-report of BV.
We conducted a nested case-control study of 200 women (100 cases and 100 controls) from a large study of 23-35 year-old African-American women 1,310 of whom were fibroid free and prospectively followed for 5 years to identify incident fibroids with standardized ultrasound examinations. We used quantitative PCR, an objective molecular method, to assess nine BV-associated and four Lactobacillus species from vaginal swab specimens. We used hierarchical logistic regression to compute odds ratios (ORs) and 95% confidence intervals (95% CIs) to examine associations between bacterial species (both individually and grouped as 1. “optimal” Lactobacillus and 2. BV-associated species) with fibroid incidence and number. We also examined vaginal imbalance (quantitatively more BV-associated bacteria than “optimal” Lactobacilli).
Contrary to our hypothesis, we found no increase in fibroid incidence or number among women with more BV-associated bacteria. High imbalance (only BV-associated bacteria, no “optimal” Lactobacillus bacteria) was actually inversely associated with fibroid incidence OR: 0.38, 95 CI (0.17-0.81).
This is the first study of ultrasound-detected incident fibroids and molecular vaginal bacterial assessment. We found no evidence that BV-associated bacteria increase the risk of fibroid incidence or number.