Hormonal milieu during implantation is crucial to embryo-endometrium interaction and to the viability of the conceptus. Alterations in the peri-implantation environment are considered to impair perinatal outcomes in intracytoplasmic sperm injection (ICSI) therapy. GnRH-a is a new and promising modality for LPS. Regimens for using GnRH-a in LPS, including single mid-luteal bolus or the addition of a GnRH-a to progesterone supplementation, have been recently suggested. The aim of this study is to evaluate the impact of addition of mid-luteal single-dose or multiple-dose GnRH agonist to the routine luteal phase support in patients undergoing ICSI cycles using GnRH antagonist protocol.