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 < 0.001), clinical pregnancy rate (73.4%, 74.4% vs 57.2%, P = 0.001), and ongoing pregnancy rate (OPR; 67.6%, 63.2% vs 51.0%, P = 0.005) compared to the HRT group. Additionally, the three groups demonstrated comparable abortion rate (7.8%, 14.9% vs 10.9%, P = 0.299). After adjusting for potential confounders in the multiple logistic regression model, the HRT protocol resulted in a 54% significantly lower OPR compared to the NC protocol (adjusted odds ratio [aOR] = 0.46, 95% confidence interval [CI]: 0.28–0.77; P = 0.003). Meanwhile, the OPR difference between the OI protocol and the NC protocol remained insignificant (OI vs NC: aOR = 0.62, 95% CI: 0.35–1.12; P = 0.112). Conclusion: The ovulatory‐FET scheme (NC and OI) following hysteroscopic polyp resection displayed promising clinical outcomes compared with HRT‐FET scheme. The regimen without exogenous estrogen administration should be prioritized for endometrial preparation protocol after polypectomy. Synopsis: Implementing an endometrial preparation protocol devoid of exogenous estrogen administration can lead to significantly better FET results after hysteroscopic polypectomy. [ABSTRACT FROM AUTHOR]