Can bacterial vaginosis influence fertility? Its increased prevalence in a subfertile population

Abstract

The possible role of bacterial vaginosis (BV) in the etiology of subfertility was investigated in a comparative study of 199 women presenting for the first time to a specialist infertility clinic in the UK and 1379 women booking at an antenatal clinic. Gram-stained vaginal smears were classified according to the Nugent score: Grade 1 (normal) Grade 2 (intermediate) and Grade 3 (BV). 87.6% of antenatal patients and 76.0% of infertility clients had normal vaginal flora. Grade 2 flora were detected in 3.9% of antenatal patients and 5.5% of infertility clients while the proportions of women with Grade 3 flora were 8.5% and 18.5% respectively. Overall 12.4% of antenatal patients and 24.0% of infertility clients had abnormal flora (Grades 2 and 3 combined). In a subgroup of 61 women for whom an infertility diagnosis was obtainable the rates of abnormal flora varied with the infertility diagnosis. While women who succeeded in achieving a spontaneous pregnancy while undergoing infertility investigation had a 9% BV prevalence women with a diagnosis of tubal infertility had a BV prevalence of 22% and an abnormal flora (Grades 2 and 3) prevalence of 33%. Chlamydial antigen was not detected in any of the 61 women in whom an infertility diagnosis had been obtained. These preliminary data suggest that the role of BV in infertility warrants further investigation.