Abstract:

Objective: To investigate the effects of two endometrial preparation protocols on the outcomes of the first frozen-thawed embryo transfer (FET) cycle after hysteroscopic endometrial polypectomy. Methods: A retrospective analysis was conducted on the clinical data of 526 patients who underwent the first FET treatment after hysteroscopic endometrial polypectomy, from January 2021 to July 2023. Patients were divided into two groups based on the endometrial preparation protocol, the hormone replacement therapy (HRT) group (Group A, 277 cases) and the gonadotropin releasing hormone agonist (GnRH-a)-HRT group (Group B, 249 cases). The general characteristics, FET cycle parameters, and pregnancy outcomes of the two groups were compared. And the influencing factors of live birth outcome were analyzed. Results: Basal luteinizing hormone, basal estradiol, anti-Müllerian hormone, endometrial thickness on the transformation day of the FET cycle, and the proportion of transferred blastocyst in Group B were all significantly higher than those in Group A (all P<0.05). The implantation rate in Group B was significantly higher than that in Group A (P=0.014). There were no significant differences in clinical pregnancy rate, miscarriage rate, ongoing pregnancy rate, and live birth rate between the two groups (all P>0.05). After controlling the confounding factors, binary Logistic regression analysis showed that the endometrial preparation protocol was not the impact factor of live birth outcome (P>0.05). Conclusions: In the first FET cycle following hysteroscopic endometrial polypectomy, both HRT protocol and GnRH-a-HRT protocol can achieve similar live birth outcome. Considering that the GnRH-a-HRT regimen involves higher treatment costs and longer treatment duration, the conventional HRT protocol may be preferred as the first choice.

Key words: Endometrium, Polyps, Embryo transfer, Hormone replacement therapy, Pregnancy outcome, Gonadotropin releasing hormone agonist-hormone replacement therapy