Luteal phase rescue in high-risk OHSS patients by GnRHa triggering in combination with low-dose HCG: a pilot study

Triggering of final oocyte maturation with gonadotrophin-releasing hormone agonist (GnRHa) has previously been shown to prevent ovarian hyperstimulation syndrome (OHSS), but at the same time a detrimental effect on clinical outcome parameters was usually reported. In this prospective, observational, proof-of-concept study, a new protocol was employed, using GnRHa to trigger final oocyte maturation in OHSS high-risk IVF/ICSI patients after co-treatment with GnRH antagonist. The aim was to avoid cycle cancellation in high-risk patients without increasing the risk of early onset OHSS and simultaneously secure the reproductive outcome. Twelve patients with ≥25 follicles ≥11 mm in diameter after ovarian stimulation were prospectively enrolled to have final oocyte maturation triggered with 0.5 mg buserelin s.c., followed by a single bolus of 1500 IU human chorionic gonadotrophin (HCG) 35 h later to rescue the luteal phase. A mean of 21.5 oocytes was retrieved. All patients underwent embryo transfer, resulting in an ongoing clinical pregnancy rate per cycle of 50% (6/12) and a live birth rate of 50% (6/12). One patient developed moderate, late onset OHSS that did not require hospitalization. GnRHa triggering of final oocyte maturation followed by one bolus of 1500 IU HCG seems to prevent early onset OHSS in high-risk patients and secure the reproductive outcome.