Serum Oestradiol Pattern during Coasting is Different in Antagonist Cycles Compared with Long Agonist Cycles in In Vitro Fertilisation

The Effect of Coasting on Intracytoplasmic Sperm Injection Outcome in Antagonist and Agonist Cycle

Background

Coasting can reduce the ovarian hyperstimulation syndrome (OHSS) risk in ovulation induction cycles before intracytoplasmic sperm injection (ICSI). This study aimed to investigate the effect of gonadotropin-releasing hormone (GnRH) agonist and GnRH antagonist protocols to controlled ovarian hyperstimulation (COH) cycles with coasting on the parameters of ICSI cycles and the outcome.

Materials and Methods

In a retrospective cohort study, 117 ICSI cycles were per- formed and coasting was applied due to hyperresponse, between 2006 and 2011. The ICSI outcomes after coasting were then compared between the GnRH agonist group (n=91) and the GnRH antagonist group (n=26).

Results

The duration of induction and the total consumption of gonadotropins were found to be similar. Estradiol (E₂) levels on human chorionic gonadotropin (hCG) day were found higher in the agonist group. Coasting days were similar when the two groups were compared. The number of mature oocytes and the fertilization rates were similar in both groups; however, the number of grade 1 (G1) embryos and the number of transferred embryos were higher in the agonist group. Implantation rates were significantly higher in the antagonist group compared to the agonist group. Pregnancy rates/embryo transfer rates were higher in the antagonist group; however, this difference was not statistically significant (32.8% for agonist group vs. 39.1% for antagonist group, P>0.05).

Conclusion

The present study showed that applying GnRH-agonist and GnRH-antago- nist protocols to coasted cycles did not result in any differences in cycle parameters and clinical pregnancy rates.