O-181 4D ultrasound guided embryo transfers statistically improve live birth rates - A randomised controlled trial

Abstract Study question Does the use of 4D ultrasound to guide embryo transfers improve live birth rates in comparison to the clinical touch technique? Summary answer 4D ultrasound guided embryo transfers (4DUS) result in significantly higher live birth rates (LBR) in comparison to those performed using the clinical touch technique (CTT)(41%vs28%). What is known already A previous Cochrane review showed ultrasound guided embryo transfers (ET) improve pregnancy outcomes in comparison to CTT; however there was a large degree of heterogeneity between the studies and the largest study in the review showed no difference between ultrasound guidance and CTT. A further study demonstrated no difference in ongoing pregnancy rates between 2D vs 3D ultrasound guided embryo transfers, however this study did not use LBR as an endpoint and did not report on procedure duration/difficultly, both of which are known to impact ET success rates. Study design, size, duration This was a prospective, open labelled randomised controlled trial comparing superiority between two techniques for ET (4DUS vs CTT). A total of 320 (n = 160/group) patients were recruited using computer generated randomisation that were centrally distributed in consecutive sealed opaque envelopes between July 2018 to December 2019. Main outcomes were clinical pregnancy rate (CPR) and LBR. Following the procedure, participants completed a survey based on their comfort and satisfaction. Participants/materials, setting, methods Inclusion criteria included single blastocyst transfer and a normal uterine cavity. Participants were recruited and randomized on the day of ET. Those allocated to the CTT group, had their embryo transferred without ultrasound, depositing the embryo 6cm from the external os. Those in the 4DUS group had their ET using transvaginal 4D ultrasonography and had their embryos deposited at the maximal implantation point (MIP). Main results and the role of chance Results were available from a total of 295 women (8% attrition rate, CTT n = 153; 4DUS n = 142)). No demographic differences between the two groups (CTT and 4DUS) were noted including age (p = 0.05), BMI (p = 0.29), duration of infertility (p = 0.94), type of infertility (p = 0.68) or embryo quality (p = 0.89). All the 4DUS and 95% of the CTT group were performed by the same practitioner. The 4DUS resulted in significantly higher CPR (50% vs 36% p = 0.015, OR 1.78 (1.12-2.84)) and LBR (41%vs 28%, p = 0.021, OR 1.77 (1.09-2.87)). There