Gonadotropin-releasing hormone agonist trigger increases the number of oocytes and embryos available for cryopreservation in cancer patients undergoing ovarian stimulation for fertility preservation

Abstract

Objective: To compare the oocyte and embryo yield associated with GnRH-agonist triggers vs. hCG triggers in cancer patients undergoing controlled ovarian stimulation (COS) for fertilization preservation.

Design: Retrospective cohort study.

Setting: Academic center.

Patient(s): Cancer patients undergoing COS with letrozole and gonadotropins or gonadotropin-only protocols for oocyte or embryo cryopreservation.

Intervention(s): Gonadotropin-releasing hormone agonist or hCG trigger.

Main outcome measure(s): Number of metaphase II (MII) oocytes or two-pronuclei (2PN) embryos available for cryopreservation were primary outcomes. Separate multivariate linear regression models were used to assess the effect of trigger type on the primary outcomes, after controlling for confounders of interest.

Result(s): A total of 341 patients were included, 99 (29.0%) in the GnRH-agonist group and 242 (71%) in the hCG group. There was no difference in the baseline demographics of patients receiving GnRH-agonist or hCG triggers. Within the letrozole and gonadotropins group (n = 269), the number (mean ± SD, 11.8 ± 5.8 vs. 9.9 ± 6.0) and percentage of MII oocytes (89.6% vs. 73.0%) available for cryopreservation was higher with GnRH-agonist triggers compared with hCG triggers. Similar results were noted with GnRH-agonist triggers in the gonadotropin-only group (n = 72) (i.e., a higher number [13.3 ± 7.9 vs. 9.3 ± 6.0] and percentage of MII oocytes [85.7% vs. 72.8%] available for cryopreservation). Multivariate linear regression demonstrated approximately three more MII oocytes and 2PN embryos available for cryopreservation in the GnRH-agonist trigger group, irrespective of cancer and COS protocol type.

Conclusion(s): Utilization of a GnRH-agonist trigger increases the number of MII oocytes and 2PN embryos available for cryopreservation in cancer patients undergoing COS for fertility preservation.

Keywords: Breast cancer; GnRH-agonist trigger; cancer; fertility preservation; ovarian stimulation.