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Published on: May 16, 2019
Catheter contamination during embryo transfer: impact on outcomes of in vitro fertilization
Asma Boughanmi1,2, Manel Hamdoun1,2, Marouen Braham2,3
1Microbiology and Biochemistry Laboratory, Aziza Othmana Hospital, University of Medicine of Tunis, Tunis El Manar University, Tunis, Tunisia.
Objective:
To evaluate the impact of embryo transfer catheter contamination on in vitro fertilization outcomes.
Design:
Prospective analytical observational study conducted over a period of 2 years and 9 months (from January 2021 to September 2023).
Subjects:
Women aged ≤42 years with a sonographically normal uterus, undergoing fresh or frozen embryo transfer with good-quality embryos.
Exposure:
Microbial contamination of the embryo transfer catheter was assessed by culture and real-time polymerase chain reaction. Vaginal and cervical samples were also analyzed by culture.
Main Outcome Measures:
Embryo transfer catheter contamination rate and its association with in vitro fertilization outcomes (pregnancy and live birth rates).
Results:
A total of 210 patients were included, 50% of whom underwent fresh embryo transfer. The rates of pregnancy and live birth were 29% and 17.5%, respectively. Culture-based analysis showed that 33.8% of catheters were contaminated with cervicovaginal microorganisms other than lactobacilli; this contamination rate was 3 times higher in fresh transfers. Positive catheter cultures were associated with significantly lower pregnancy and live birth rates (8.5% vs. 39.6% and 4.2% vs. 24.4%, respectively). The main bacterial species isolated were Streptococcus agalactiae (n = 31), Actinomyces spp. (n = 9), and Gardenerella vaginalis (n = 8). Conversely, the presence and abundance of Lactobacillus species on the catheter tip were associated with improved in vitro fertilization outcomes. Polymerase chain reaction detected Gardenerella vaginalis and urogenital mycoplasmas in 31.9% and 13.8% of patients, respectively. Overall, when all methods were combined, catheter contamination was observed in 58.1% of cases; it was 6 times higher in women with bacterial vaginosis. In multivariate analysis, a positive catheter culture was the only independent factor associated with failure to achieve pregnancy and live birth.
Conclusion:
Catheter contamination, particularly by cultivable microorganisms other than Lactobacillus species, constitutes an independent factor associated with in vitro fertilization failure. Guidelines for infertility management should be updated to include both clinical and microbiological parameters to enhance assisted reproductive technologies' diagnostic and therapeutic strategies.
