Relationship of vaginal bacteria and inflammation with conception and early pregnancy loss following in-vitro fertilization

Objective: The aim of this study was investigate the impact of vaginal flora and vaginal inflammation on conception and early pregnancy loss following in-vitro fertilization (IVF). Methods: We enrolled 91 women who were undergoing IVF. At embryo transfer (ET), all of the women had quantitative vaginal culture, ET catheter-tip culture, and vaginal Gram stain scored for bacterial vaginosis and quantitated for polymorphonuclear leukocytes (PMNs). Conception and early pregnancy loss were compared with culture and Gram stain results. Statistical analyses included the Chi-square test, Fisher’s exact test and the Mann-Whitney U-test. Results: The overall live birth rate (LBR) was 30% (27/91), and the rate of early pregnancy loss was 34% (14/41). In women with bacterial vaginosis, intermediate flora and normal flora, the conception rates were 30% (3/10), 39% (12/31) and 52% (26/50), respectively (p = 0.06 for trend). Early pregnancy loss occurred in 33% (1/3), 42% (5/12) and 31% (8/26) of women, respectively (p = 0.06, comparing intermediate and normal flora). The vaginal log concentration of hydrogen peroxide-producing lactobacilli was 7.3 ± 1.7 in women with a live birth (n = 27) and 4.9 ± 2.5 in those with early pregnancy loss (n = 14) (p = 0.1). Conclusions: IVF patients with bacterial vaginosis and with a decreased vaginal log concentration of hydrogen peroxide-producing lactobacilli may have decreased conception rates and increased rates of early pregnancy loss. A larger prospective treatment trial designed to evaluate the impact on IVF outcomes of optimizing the vaginal flora prior to IVF may be warranted.