The exogenous progesterone-free luteal phase: two pilot randomized controlled trials in IVF patients

Is the reproductive outcome similar after gonadotrophin-releasing hormone agonist (GnRHa) trigger followed by luteal human chorionic gonadotrophin (HCG) boluses compared with HCG trigger and a standard luteal phase support (LPS)?

Two open-label pilot randomized controlled trials (RCT) with 250 patients from 2014 to 2019, with a primary outcome of ongoing pregnancy per embryo transfer. Patients with ≤13 follicles on the trigger day were randomized (RCT 1) to: Group A (n = 65): GnRHa trigger followed by a bolus of 1500 IU HCG s.c. on the oocyte retrieval day (ORD) and 1000 IU HCG s.c. 4 days later, and no vaginal LPS; or Group B (n = 65): 6500 IU HCG trigger, followed by a standard vaginal progesterone LPS. Patients with 14-25 follicles on the trigger day were randomized (RCT 2) to Group C (n = 60): GnRHa trigger followed by 1000 IU HCG s.c. on ORD and 500 IU HCG s.c. 4 days later, and no vaginal LPS; or Group D (n = 60): 6500 IU HCG trigger and a standard vaginal LPS.

In RCT 1, the ongoing pregnancy rate was 44% (22/50) in the GnRHa group versus 46% (25/54) in the HCG trigger group (RR 0.95, 95% CI 0.62-1.45). No ovarian hyperstimulation syndrome (OHSS) was seen in Groups A or B. In RCT 2, the ongoing pregnancy rate was 51% (25/49) in the GnRHa group versus 60% (31/52) in the HCG trigger group (RR 0.86, 95% CI 0.60-1.22). The OHSS rates were 3.3% and 6.7%, respectively.

Although a larger-scale study is needed before standard clinical implementation, the present study supports that the exogenous progesterone-free LPS is efficacious, simple and patient-friendly.