Abstract
While triggering oocyte maturation with GnRH agonist (GnRHa) seems to be safe and effective in terms of the risk of developing OHSS and the number of metaphase II oocytes, it nevertheless results in luteal phase deficiency. To date, strategies have been developed in order to rescue defective luteal phase of GnRHa triggered cycles. Our study aimed to assess the reproductive outcome of GnRHa triggered cycles combined with modified luteal support (1500 IU hCG at the day of oocyte retrieval) in women with high ovarian response and to compare the outcome with hCG triggered cycles in GnRH antagonist IVF-ICSI procedures. A retrospective cohort database review of the results of GnRH antagonist IVF-ICSI cycles was conducted at a tertiary-care IVF center in Ljubljana, Slovenia. A total of 6126 cycles, performed from January 1, 2014, to December 31, 2020, were included in the final analysis. Final oocyte maturation was performed with either 5000, 6500, or 10,000 IU hCG (women with normal ovarian response) or 0.6 mg GnRHa (buserelin), supplemented with 1500 IU hCG on the day of oocyte retrieval (in women with high ovarian response). In cases of excessive ovarian response and/or high risk of OHSS luteal support was not introduced and all good quality blastocysts were frozen. According to significant differences in patients' age and the number of oocytes in the two groups, matching by age and number of oocytes was performed. No significant differences were observed regarding pregnancy rate per embryo transfer, rate of early pregnancy loss, and livebirth rate per pregnancy between the GnRHa and hCG trigger groups, respectively. A significant difference in the number of developed embryos and blastocysts, as well as the number of frozen blastocysts, was seen in favor of the GnRHa trigger. However, the birth weight in the GnRHa trigger group was significantly lower. CONCLUSION: The results of our study support the use of GnRHa for final oocyte maturation in GnRH antagonist IVF cycles in women with high ovarian response. Luteal phase rescue was performed by co-administration of 1500 IU hCG on the day of oocyte retrieval and estradiol and progesterone supplementation. In our experience, such an approach results in a comparable reproductive outcome with hCG trigger group.