Clinical features and outcomes of IVF-ET cycles between GnRH antagonist and GnRH agonist long protocol in normal responders: a comparison of 266 cases

Abstract

Objective To analyze and compare the clinical features and outcomes of in vitro fertilization-embryo transfer (IVF-ET) cycles in normal responders using gonadotrophin (Gn) releasing hormone (GnRH) antagonist or GnRH agonist long protocol. Methods The clinical data of patients who received IVF treatment and had normal ovarian response to GnRH antagonist or GnRH agonist long protocol in our reproductive center from January 2017 to March 2019 were collected. According to the treatment protocol and the fresh embryo transplanted or not, these patients were divided into Group A (receiving GnRH antagonist, but no fresh embryo transplanted, n=128), Group B (GnRH antagonist, with fresh embryo transplanted, n=138), and Group C (GnRH agonist long protocol, with fresh embryo transplanted, n=720). Besides, the frozen embryo transfer (FET) cycles of Group A were analyzed, and served as Group D. The thickness of endometrium on luteal conversion day and outcome of Group D were compared with those of Group B and Group C. Results ① The duration and dosage of Gn were shorter and less in Group A and B than Group C, and statistical difference was seen in Gn duration (P < 0.05), and in Gn dosage only between Group A and C (P < 0.05). ②On HCG day, the serum estradiol (E2) level were lower in Group A and B than Group C (P < 0.05), the endometrium of Group C was the thickest, and the thickness of endometrium on luteal conversion day of Group D was lower than that on the HCG day of Group A, B and C, where the differences between Group A and B, and Group C and D were statistically significant (P < 0.05). ③ The number of oocytes obtained in Group A and B were less than that in Group C (P < 0.05), but there were no statistical difference in metaphase Ⅱ (MⅡ) oocyte rate, normal fertilization rate and high-quality embryo rate among Group A, B and C. ④ Biochemical pregnancy rate and clinical pregnancy rate had no statistical differences among Group B, C, and D (P < 0.05). Group B had the lowest implantation rate but the highest miscarriage rate, and had obvious differences with Group C (P < 0.05). Conclusion GnRH antagonist protocol can obtain similar oocytes and embryos as the GnRH-a long protocol in normal response population. However, the antagonist may exert negative impact on endometrial receptivity and result in low pregnancy rate and high abortion rate.

Keywords

• gnrh antagonist protocol
• normal response population
• in vitro fertilization-embryo transfer