High vaginal load of Atopobium vaginae reduces the interval time to delivery in high risk pregnancies

Background: Bacterial vaginosis (BV) has been suggested to be a risk factor of prematurity. However, the current methods for its diagnosis are mainly based on clinical score and/or Gram staining. They are fastidious, lack of precision, and difficult to reproduce. The aim of this study was to rationally evaluate the link between vaginal flora anomalies and prematurity using molecular methods. Methods & Materials: A prospective multicenter national study was performed: 813 high risk pregnant women with late abortion, previous preterm delivery, and/or short cervix diagnosed by ultrasound were included. Quantitative molecular analyses were performed using specific real-time polymerase chain reaction assays and serial dilutions of a plasmid suspension targeting Atopobium vaginae, Gardnerella vaginalis, Mycoplasma hominis, Lactobacilli,and a human gene. Results: High vaginal loads of A. vaginae (≥105/ml) was systematically and significantly linked before 22, 28, and 32 weeks to a shorter interval for delivery. This time was: 152.1 and 413.2 days (p = 0.003; Hazard ratio [HR], 6.6; 95% Confidence Interval [CI] 1.922.6) before 22 weeks, 149.2 and 400.6 days (p = 0.036; HR, 2.8; 95% CI, 1.1-7.6) before 28 weeks, and 132.5 and 365.1 days (p = 0.017; HR, 2.3; 95% CI, 1.2-4.5) before 32 weeks. High vaginal loads of G. vaginalis (≥105/ml) was significantly linked to a shorter interval time to delivery before 22 weeks only; the mean interval was 174.1 and 412.9 days (p = 0.028; HR 3.9; 95% CI, 1.2-13.5). Low vaginal loads of Lactobacilli (≤105/ml) were also significantly linked to a shorter interval time to delivery before 22 weeks only; the mean interval was 169.4 and 415.4 days (p = 0.024; HR 0.2; 95% CI, 0.10.8). The differences remain significant only for high vaginal loads of A. vaginae (≥105/ml) and delivery before 22 weeks (p = 0.014) after multivariate analysis. Conclusion: In high risk women, there is a specific link between high vaginal loads of A. vaginae and abortion before 22 weeks.