Received June 01, 2015
Accepted August 14, 2015

Objective: To compare the use of GnRH agonist (GnRHa) or hCG trigger in potential OHSS patients undergoing freeze-all programs. We also compared the clinical outcomes when fresh versus freeze-thawed embryo transfers were performed in cycles with a high number of retrieved oocytes. Methods: The study included potential OHSS patients who received GnRHa (n=74) or hCG (n=49) trigger. The protocols were compared with respect to the clinical outcomes. We also compared the clinical outcomes of cycles in which hCG trigger was used and more than 20 MII oocytes were retrieved when: fresh embryo transfer protocol (n=153) or freeze-all protocol (n=123) were performed. Results: A decreased serum estradiol level, a decreased number of retrieved oocytes, an increased MII retrieved rate, and decreased fertilization rate was observed in the hCG when compared with the GnRHa group. No significant differences were noted concerning clinical outcomes. When fresh cycles were compared with frozen-thawed cycles, the estradiol serum level and the number of cryopreserved embryos were higher in the frozen-thawed cycles. The clinical pregnancy rate was higher among freeze-all cycles, as well as the implantation and cumulative pregnancy rates, when compared with fresh embryo transfer cycles. Conclusion: The use of GnRHa trigger may be a good alternative to prevent the OHSS in patients presenting an extreme ovarian response to COS, leading to similar clinical outcomes, when compared with the traditional hCG trigger. Moreover, our findings demonstrated that the strategy of freezing-all embryos not only decreases the risk of OHSS but also leads to a better pregnancy rate.