Purpose:The aim of this project is to prospectively determine whether a single dose of GnRH-agonist administered at the time of implantation increases or not the reproductive outcome in patients undergoing in vitro fertilization ( IVF)/ intracytoplasmatic sperm injection(ICSI) triggered by a GnRH-agonist followed by a small bolus of human chorionic gonadotropin (hCG 1500 IU) the day of oocyte retrieval.

It has been reported in previous publications that the ovarian hyperstimulation syndrome (OHSS) was eliminated when GnRH agonist was used to trigger ovulation and the delivery rate has improved after modified luteal support especially when a small bolus of hCG is used on the day of oocyte retrieval. (OMEGA/HCG 1500 IU). However, a risk difference of 7% in delivery rates is still in favor of HCG trigger. Thus, further modifications in the luteal phase supplementation are required in order to optimise the reproductive outcome after GnRH-agonist triggering. Recently, many papers showed, that independently of the GnRH analogue used to prevent the premature LH surge, the addition of GnRH-agonist during the luteal phase seems to be beneficial in terms of pregnancy. Nevertheless, their use in practice is not yet admitted because of controversial results in terms of efficacy and safety particularly on the conceptus.