I-25: GnRHa Trigger State of the ART -Towards the OHSS Free Clinic

Human chorionic gonadotropin (hCG) has been used as a surrogate for the mid-cycle LH surge for several decades. Due to structural and biological similarities with LH, hCG binds to and activates the same receptor - the LH/hCG receptor. However, despite the fact that hCG effectively secures final oocyte maturation and ovulation, its use as a surrogate for LH has got several drawbacks - first and foremost a sustained luteotropic effect, facilitating ovarian hyperstimulation syndrome (OHSS). Recently GnRH antagonist protocols for the prevention of a premature LH surge were introduced, allowing final oocyte maturation to be triggered with a single bolus of a GnRH agonist (GnRHa). GnRHa is as effective as hCG for the induction of ovulation, and in addition to the LH surge a FSH surge is also induced, resembling the natural mid-cycle surge of gonadotropins. The first prospective randomized studies reported a poor clinical outcome when GnRHa was used to trigger final oocyte maturation in IVF/ICSI, due to a luteal phase deficiency, despite standard luteal phase supplementation with progesterone and estradiol. As GnRHa triggering of final oocyte maturation possesses advantages over hCG triggering in terms of a reduced, if not eliminated risk of OHSS, the retrieval of more mature oocytes, and a higher patient convenience, the challenge has been to rescue the luteal phase. The development of the present protocol for luteal phase rescue after GnRHa trigger, employing a so called modified luteal phase support will be presented. The paramount aim has been to improve pregnancy rates after GnRHa trigger without increasing the OHSS rate. Although fine tuning of the luteal phase support is still possible, GnRHa triggering is now a valid alternative to hCG trigger with potential benefits. MC questions GnRHa trigger elicits a surge of gonadotropins with duration of: 1. 48 hours 2. 20 hours 3. 24-28 hours 4. 40 hours 5. < 20 hours GnRHa trigger may be used in: 1. All patients 2. PCOS patients only 3. At a smaller follicular size than HCG trigger 4. Patients transferred without a modified luteal phase support 5. All patients except the hypo/hypo patient.