Gonadotropin-releasing hormone agonist combined with hormone replacement therapy improves pregnancy outcome in intrauterine adhesion

Objective: This retrospective study aimed to explore the optimal endometrial preparation method in women with intrauterine adhesions (IUAs).Method: A total of 882 frozen-thawed embryo transfer (FET) cycles were categorized into three groups based on endometrial preparation methods: hormone replacing therapy cycle (HRT, n=636), natural cycle (NC n=174), and HRT with GnRH-a pretreatment (HRT+GnRH-a, n=72. Logistic regression was performed to investigate the association between cycle regimens and pregnancy outcomes. Subgroup analysis of IUAs combined with thin endometrium (≤7mm) was also performed.Results: HRT with GnRH-a pretreatment was associated with higher incidences of clinical pregnancy, ongoing pregnancy, and live birth, but lower early miscarriage compared with either HRT or NC. Logistic regression indicated that after controlling for potential confounders, the incidences of live birth (HRT+GnRH-a as reference; NC: aOR=0.577, 95%CI 0.304-1.093; HRT: aOR=0.434, 95%CI 0.247-0.765) and ongoing pregnancy (NC: aOR=0.614, 95%CI 0.324-1.165; HRT: aOR=0.470, 95%CI 0.267-0.829) remained significantly higher in HRT+GnRH-a compared to those in HRT, but comparable to those in NC. While there was no significant difference with respect to the clinical pregnancy rate (NC: aOR=0.695, 95%CI 0.374-1.291; HRT: aOR=0.650, 95%CI 0.374-1.127) and early miscarriage rate (NC: aOR=1.734, 95%CI 0.417-7.175; HRT: aOR=2.594, 95%CI 0.718-9.378) between groups. Subgroup analysis suggested there was no priority of endometrial preparation method in IUAs combined with thin endometrium.Conclusion: HRT with GnRH-a pretreatment improves pregnancy outcomes in women with history of IUAs. GnRH-a may restore the endometrial receptivity in the FET cycles in IUAs.