GnRH antagonist rescue protocol combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome: a randomized controlled trial

Background: The aim of this study was to compare the efficacy of antagonist rescue protocol (replacing GnRH agonist with GnRH antagonist and reducing the dose of gonadotropins) combined with cabergoline versus cabergoline alone in the prevention of ovarian hyperstimulation syndrome (OHSS) in patients pretreated with GnRH agonist long protocol who were at high risk for OHSS.

Methods: Two hundred and thirty six patients were randomized in a 1:1 ratio to the cabergoline group or the antagonist rescue combined with cabergoline group. Both groups received oral cabergoline (0.5 mg/day) for eight days beginning on the day of HCG administration. In the antagonist rescue combined with cabergoline group, when the leading follicle reached 16 mm, GnRH agonist (triptorelin) was replaced with GnRH antagonist (cetrorelix acetate) and the dose of HP-uFSH was reduced to 75 IU/day. HCG (5,000 IU/I.M) was administered when the serum estradiol level dropped below 3500 pg/ml. The study was open label and the outcome assessors (laboratory staff and the doctor who performed oocyte retrieval) were blind to treatment allocation.

Results: The incidence of moderate/severe OHSS was significantly lower in the antagonist rescue combined with cabergoline group [5.08 % Vs 13.56 %, P value =0.025, OR = 0.342, 95 % CI, 0.129-0.906]. Four cycles were cancelled in the cabergoline group. There were no significant differences between the groups with respect to the number of retrieved oocytes, metaphase II oocytes, high quality embryos and fertilization rate. Moreover, the implantation and pregnancy rates were comparable between both groups.

Conclusion: GnRH antagonist rescue protocol combined with cabergoline is more effective than cabergoline alone in the prevention of OHSS.

Trial registration: Clinical trial.gov ( NCT02461875 ).