Repeated Doses of GnRh Agonist versus Single Bolus of hCG for Luteal Phase Support after GnRH Agonist Trigger for Ovulation: a Prospective Randomised Controlled Study

Introduction: Use of GnRH agonist (GnRHa) trigger for ovulation induction prevents the development of severe ovarian hyperstimulation syndrome (OHSS) in patients at risk.

Aim: To compare repeated doses of GnRHa with a single bolus of 62.5 mcg hCG as luteal phase support for patients treated with GnRHa trigger for ovulation.

M&M: In this prospective, randomized controlled study, patients at-risk for developing OHSS were treated with GnRH antagonist protocol and a GnRHa trigger for ovulation. An E₂ level ≥2500 pg/ml was used to trigger ovulation with GnRHa instead of the classic hCG trigger. Patients were randomized to receive a single bolus of 62.5 mcg hCG on day 3 following oocyte pick-up or repeated doses of GnRHa (decapeptyl) 0.1 mg every two days from day 3 following oocyte pick until pregnancy test.

Results: Both groups were comparable in age, BMI and E₂ at hCG, as well as in number of oocytes retrieved. Progesterone levels increased from day 3 to day 6 (from 27.2±14 to 48.5±32 ng/ml in GnRHa group and from 23.2±28 to 45.7±20 ng/ml in the hCG group). LH level on day 6 was higher in the GnRHa group compared to the hCG group (3.0±2 vs. 0.22±0.1 IU/l, P=0.01). Clinical pregnancy rates were 45% in the GnRHa group and 44% in the hCG group (P=0.57). OHSS was reported in one in hCG group patient.

Conclusion: Both strategies seem to be efficacious for luteal phase support. Repeated GnRHa doses seem to be safer.