Impact of ultrasound operator training on clinical pregnancy rates during embryo transfer: a retrospective cohort study

Introduction: While various aspects of the embryo transfer (ET) procedure have been studied for their potential impact on treatment outcomes, the influence of ultrasound (US) operator guidance during ET has not been extensively explored. Therefore, this study aims to investigate the impact of US guidance performed by well-trained versus untrained medical staff on the clinical pregnancy rate. Material and methods: This is a retrospective study that was conducted in a single university-affiliated IVF unit between February 2023 and April 2024. The study compared the clinical pregnancy rate between patients undergoing ET by an US operator versus an untrained operator. Results: A total of 951 embryo transfers were analyzed: 442 performed by trained operators (46.5%) and 509 by untrained operators (53.5%). Demographic characteristics were comparable. Main diagnosis, day of transfer, and mean number of embryos transferred were similar between groups (p = 0.2, 0.3, 0.4, respectively). The main outcome measure, clinical pregnancy crude rate, was similar (31.6% untrained vs. 31.4% trained, p = 0.9). Factors identified as associated with achieving a clinical pregnancy were maternal age (p < 0.01), endometrial thickness (p = 0.012), type (frozen vs. fresh) of embryos (p = 0.029), and embryonal age (p = 0.012). In a conditional logistic regression analysis, the US operator was not found to be a significant effector. Conclusions: The utilization of a trained versus untrained ultrasound operator during ET was not associated with a difference in clinical pregnancy rates.