Different endometrial preparation protocols on first frozen–thawed embryo transfer outcomes after hysteroscopic polypectomy: A retrospective cohort study

Objective To evaluate the optimal endometrial preparation protocol for frozen–thawed embryo transfer (FET) following hysteroscopic polypectomy. Methods This was a retrospective clinical cohort study involving 464 patients who underwent their first FET after polyp resection between January 2021 and July 2023. The cohorts were categorized into three groups: the natural cycle (NC) group (n = 139), the ovarian induction (OI) group (n = 117), and the hormone replacement therapy (HRT) group (n = 208). Results In the initial unadjusted analysis, both NC and OI cycles exhibited similar pregnancy rates but were associated with significantly higher implantation rate (56.5%, 57.1% vs 42.0%, P