[Onset and maintenance of the luteal phase with GnRH agonists or hCG in cycles under GnRH antagonists].

Corpus luteum function seems to be impaired in IVF cycles with COH (Controlled Ovarian Hyperstimulation) and GnRH antagonist. Support of corpus luteum function remains mandatory after ovarian stimulation for IVF with GnRH antagonist cotreatment. GnRH antagonists do not have any impact on the luteal phase of IVF/ICSI cycles when hormonal support is given. A new treatment option for patients undergoing ovarian stimulation is the gonadotrophin-releasing hormone (GnRH) antagonist protocol, with the possibility to trigger a mid-cycle LH surge using a single bolus of GnRH agonist, reducing the risk of developing ovarian hyperstimulation syndrome (OHSS) in high responders. In IVF cycle with COH and GnRH antagonist, support of corpus luteum function is essential, whatever molecule to trigger LH surge (hCG, r-hLH, GnRH agonist). Adequate luteal support (progesterone and estrogens) compensates for luteolysis and assures good clinical outcome.