Gonadotropin Releasing Hormone (GnRH) Antagonist Administration to Decrease the Risk of Ovarian Hyperstimulation Syndrome in GNRH Agonist Cycles Triggered with Human Chorionic Gonadotropin

Purpose: In Gonadotropin releasing hormone(GnRH) agonist IVF, after administration of human chorionic gonadotropin(HCG) triggering, there is a risk of ovarian hyperstimulation syndrome(OHSS). Few methods exist to prevent OHSS in these cases. Therefore, we investigated the use of a GnRH antagonist to decrease the risk of OHSS, due to its ability to decrease VEGF production and function.

Method: A retrospective cohort study of 171-IVF patients at risk for developing OHSS after a GnRH agonist cycle with HCG trigger was performed from 2011 to 2019. The patient population consisted of women with an unexpected exuberant response to stimulation based on ovarian reserve testing and were triggered with hCG. Women were converted to a freeze-all cycle and received either cabergoline 0.5 mg orally alone for 7 days from the collection(Group 1, n = 123) or received cabergoline 0.5 mg orally and ganirelix, 250 mcg SC for 7-10 days(Group 2, n = 48).

Results: Group 1 had more cases of moderate and severe OHSS than group 2-(25% vs. 10% p = 0.03, and 52% vs. 25% p = 0.001 respectively). Group 1 reported more abdominal discomfort and bloating than group 2(91% vs. 65% p < 0.001) and the presence of free fluid was more frequent in group 1 than group 2(74% vs. 35% p < 0.001). Hemoconcentration and electrolyte disturbances were less severe in group 2 than in group 1 (p < 0.001 all cases).

Conclusion: In patients at high risk for developing OHSS after hCG trigger in a GnRH agonist cycle, the addition of GnRH antagonists in the luteal phase may reduce the risk of developing moderate and severe OHSS. The GnRH antagonist likely leads to more rapid luteolysis and down regulation of VEGF production and receptor response, thereby decreasing the hallmark increased vascular permeability.