The live birth rate improved when the endometrial thickness decreased from the HCG day to the embryo transfer day. A retrospective cohort study of 9572 fresh embryo transfer cycles
Author(s): Miao Wang, Xinglin Wang, Ying Meng, Fang Wang, Hong Ye
To investigate whether decreased endometrial thickness from the HCG trigger day to the embryo transfer day affects the pregnancy outcomes of IVF/ICSI cycles.
A retrospective single-center cohort study was conducted. In total, 9572 first IVF/ICSI embryo transfer cycles involving the long protocol at Chongqing Reproductive and Genetic Institute from January 1, 2016, to June 30, 2020were included. The 9572 cycles were divided into 2 groups based on whether the endometrial thickness decreased from the HCG trigger day to the embryo transfer day. The outcomes of the two groups were compared. The primary outcome was live birth rate (LBR). The secondary outcomes were clinical pregnancy rate (CPR), pregnancy loss rate (PLR) and ectopic pregnancy rate (EPR).
The LBR of participants in the decreased endometrial thickness group was higher than that in the non-decreased group (54.26% vs. 51.67%, P=0.023, after adjusting the confounding factors P=0.032), and the CPR in the decreased group was also higher than that in the non-decreased group (61.36% vs. 58.88%, P=0.027, after adjusting confounding factors P=0.037). There was no significant difference in the EPR (1.65%vs. 1.82%, P = 0.513) or pregnancy loss rate (6.85%vs. 7.42% P = 0.771) between two groups.
A properly decreased of endometrial thickness from the HCG trigger day to the embryo transfer day in IVF/ICSI cycles will increases the LBR and CPR. Therefore, the decreased endometrial thickness from the HCG trigger day to the embryo transfer day cannot be the determined factor of cancelling embryo transfer.