Rates of bacterial vaginosis in women undergoing in vitro fertilisation for different types of infertility

Objective To assess whether the rate of bacterial vaginosis (BV) is higher in women with tubal factor infertility compared with those with other causes of infertility. Design Cross-sectional study. Setting Assisted conception unit of a teaching hospital in Leeds. Population Consecutive women undergoing in vitro fertilisation. Methods Women undergoing in vitro fertilisation (IVF) had a vaginal smear taken at the time of their egg collection. The smear was Gram-stained and graded as normal, intermediate or BV. Main outcome measures The presence of bacterial vaginosis and the causes of infertility. Results A total of 749 women were included. The vaginal smears were normal in 63.6%, intermediate in 12.1%, and BV in 24.3%. The rates of BV in women with different types of infertility were 36.4% in tubal factor, 15.6% in male factor, 33.3% in anovulation, 12.5% in endometriosis and 18.9% in unexplained infertility. After controlling for the effects of age and smoking using a multivariate logistic regression model, women with tubal infertility were significantly more likely to have BV than women with endometriosis OR 3.63 (95% CI 1.52–8.67); male factor OR 2.98 (95% CI 1.80–4.90); and unexplained infertility OR 2.20 (95% CI 1.35–3.59). The adjusted figures for the increase of BV in women with anovulation were: endometriosis OR 3.77 (95% CI 1.28–11.08); male factor OR 3.09 (95% CI 1.37–6.96); and unexplained infertility OR 2.29 (95% CI 1.02–5.12). Conclusions Women with tubal infertility were three times more likely to have BV than women with endometriosis, male factor or unexplained infertility. These findings support the association between BV, pelvic inflammatory disease (PID) and tubal damage but do not help distinguish between cause and effect. Women with anovulation were also three times more likely to have BV than women with endometriosis or male factor infertility, supporting suggestions of hormonal influence on vaginal flora.