INTRODUCTION: The aim of this observational retrospective cohort study was to define the effect of the Embryo Transfer (ET) technique on pregnancy and live birth rates.
METHODS: Infertile women with good prognostic factors undergoing in vitro fertilization treatment with freezing all 5th day good quality embryos and consecutive frozen embryo transfer in 468 infertile good responders with first quality 5th day embryos where chosen for this study. Logistic regression analysis was performed to determine the effect of embryo transfer on the live birth rates.
RESULTS: Of the six predictive values, four were statistically significant: the easy passage of the external catheter, ultrasonographic visualization of the bubble, leaving the embryo at the desired location, and bleeding found in the external catheter after the catheter was excluded from the cervical ostium. While the probability of pregnancy decreased by 98.1% in cases where the embryo could not be left at the expected location, it was observed that the probability of pregnancy decrease was 96.4% in cases where no bubble could be seen, and 59.2% in cases with bleeding in the external catheter. Similarly, a 74.4% decrease in the probability of pregnancy was observed in patients in whom the passage of the catheter was difficult. Even though the tip of the transfer catheter during the ET is easily seen, the blood in the external catheter decreases pregnancy chance.
DISCUSSION AND CONCLUSION: Visualizing the internal catheter and the air bubble under the ultrasound guidance with the atraumatic placing of the embryo 1-1.5 cm away from the uterine fundus is crucial for the success of embryo transfer.