Ultrasound-guided embryo transfer: Does it improve IVF success?

Abstract

Objective: Recent studies have suggested that ultrasound-guided embryo transfer (U/S-guided ET) may improve the outcome in in-vitro fertilization (IVF). In our center, we perform trial ET without U/S guidance in preparation for actual ET. The goal of our study is to determine if U/S guidance may better our ability to perform ET. Design: Prospective observational study. Materials and Methods: Patients at a university-based IVF center undergoing traditional IVF transfer were offered embryo transfer under abdominal ultrasound (U/S) guidance. Sixty-seven consecutive patients underwent ultrasound-guided embryo transfer from January 2003 to March 2003. Patients in the study had full bladders at the time of ultrasound-guided embryo transfer and all transfers were performed with a Wallace catheter by the same physician. At time of transfer, the catheter tip was placed approximately 1.5 cm from the fundus as measured by abdominal ultrasound. The embryos were transferred subsequently under U/S visualization. Total cavity length by ultrasound (length of catheter within the uterus and cervix + length from tip of catheter to the fundus by ultrasound) was compared to the length of the cavity as noted by trial transfer. A difference of 1.5 cm or greater was considered as a significant difference. Patients were grouped as having a difference of 1.5 cm from the trial transfer (Group A) or having no difference (Group B), however, all embryos were placed within 1–2 cm of the fundus by U/S. IVF outcomes were evaluated. Results: Ten patients (15.9%) had a difference of > 1.5 cm from the trial transfer (group A). Between groups, there was no difference in age, number of eggs retrieved, number of mature eggs, or number of embryos transferred. Four patients were excluded from the study as their bladders were empty at the time of embryo transfer, thus making visualization of the cavity difficult. The overall pregnancy rate was 60.3% (38/63). The pregnancy rate for group A was 60% (6/10 patients) while the pregnancy rate for group B was 60.4% (32/53 patients), p = 0.98. When the patients were segregated by transfer < 1.5cm from the fundus by U/S (group C) vs > 1.5 cm by U/S (group D), the pregnancy rates were 51.7% (15/29 group C) and 67.6% (23/34 group D), p = 0.19. Conclusion: In our analysis, 15% of patients had a discrepancy of > 1.5 cm noted at the time of ultrasound-guided embryo transfer when compared to the cavity length at trial transfer. This suggests a benefit to U/S-guided ET. Furthermore, our study suggests a trend for better outcome with transfer between 1.5 to 2 cm from the fundus. A prospective randomized trial comparing ultrasound-guided transfer with the traditional blind transfer is required to further assess if ultrasound-guided transfer should be used in all cases of embryo transfer.