Effects of pretreatment with long-acting gonadotropin-releasing hormone agonists on pregnancy outcomes in patients with minimal and mild peritoneal endometriosis: A retrospective study of 274 frozen-thawed embryo transfer cycles

To investigate the effects of pretreatment with long-acting gonadotropin-releasing hormone agonist (GnRH-a) before frozen-thawed embryo transfer (FET) on pregnancy outcomes in patients after minimal-mild (stages I-II) peritoneal endometriosis surgery. A retrospective cohort study was performed from March 2018 to May 2019. Overall, 274 patients met inclusion criteria of undergoing FET after minimal/mild peritoneal endometriosis surgery. For the FET protocol, patients were divided into 2 groups: GnRH-a plus hormone replacement therapy (HRT) (group A, n = 154) and HRT-only (group B, n = 120), with the former divided into 2 subgroups receiving 1 (group A1, n = 80) or 2 doses (group A2, n = 74) of GnRH-a. Basic characteristics and pregnancy outcomes of groups A and B and groups A1 and A2 were compared. Clinical pregnancy rate (CPR) and live birth rate (LBR) were the primary outcomes and logistic regression was used to analyze independent correlation factors. The CPR and LBR in group A were 58.4% and 50.0%, respectively, and were not significantly higher than in group B (49.2% and 40.0%; respectively,chi(2) = 2.339, P = .126 and chi(2 )= 2.719, P = .099, respectively). CPR and LBR in group A1 were not significantly lower than those in group A2 (52.5% and 45.0% vs 64.9% and 55.4%, respectively; chi(2) = 2.420, P = .120 and chi(2) = 1.665, P = .197, respectively). However, group A2's CPR and LBR were significantly higher than group B's (64.9% and 55.4% vs 49.2% and 40.0%, respectively; chi(2) = 4.560, P = .023 and chi(2) = 4.375, P = .026, respectively). Logistic regression analysis showed that GnRH-a pretreatment (1 or 2 doses) had no significant effect on CPR and LBR compared with the HRT-only group. Patients with minimal-mild (stages I-II) peritoneal endometriosis surgery may not require GnRH-a pretreatment before FET.