Bacteria in the transfer catheter tip influence the live-birth rate after in vitro fertilization

Objective: To assess the impact of individual bacteria isolated from the vagina and tip of the embryo transfer catheter on live-birth rates. Design: Prospective clinical study. Setting: Infertility outpatient clinic of a university hospital. Patient(s): Ninety-one women undergoing IVF-ET. Intervention(s): Cultures were obtained from the vagina for aerobic and anaerobic bacteria at the time of both sonographic egg retrieval and embryo transfer and from the tip of the embryo transfer catheter. Doxycycline treatment was started after egg retrieval. Main Outcome Measure(s): The live birth of one or more neonates. Result(s): Doxycycline had no substantial impact on the recovery of individual vaginal bacteria or on bacterial vaginosis. An increase in live-birth rate was associated with the recovery of hydrogen peroxide–producing Lactobacillus from the vagina ( P=0.01) and from the embryo transfer catheter ( P=0.01). In contrast, a reduction in live-birth rate was associated with recovery of Streptococcus viridans ( S. viridans) from the embryo transfer catheter tip ( P=0.04). Conclusion(s): In the setting of IVF-ET, prophylactic doxycycline had little effect on vaginal bacteria. Specific bacteria recovered from the embryo transfer catheter appear associated with a detrimental or beneficial effect or with no effect on live-birth rates.