Comparison of Pregnancy Rates after Luteal Phase Support Therapy with GnRH Agonist versus Progesterone: Prospective Randomized Study

Gilad Avigdor Eadit Buhbut Rinad Nabulsi Ido Ben Ami Talya Eldar Geva Gal Michael Avi Tsafrir Hyman Jordana Hadassah Naama Srebnik Einat Zivi Olshinka Keren Rotshenker Karen Kochan Reut Meir
IVF and Infertility Unit, Shaare Zedek Medical Center and Faculty of Medicine, Hebrew University of Jerusalem, Israel

Introduction:
Patients who undergo fresh embryo transfer are treated with luteal phase support, in order to increase pregnancy rates. This study aims to compare the efficacy and safety of GnRH agonist (GnRH-a) versus progesterone for luteal support, in an antagonist-based protocol triggered with hCG.

Methods:
Prospective randomized study of patients who underwent antagonist-based IVF cycles triggered with hCG. Criteria for inclusion were patients aged between 18-45, BMI between 19-35, infertility diagnosis of male factor, tubal factor, anovulation, age-related, unexplained, and PGT. Exclusion criteria were triggering with agents other than hCG, previous 3 or more failed cycles, endometriosis, hydrosalpinx, hypogonadotropic hypogonadism and Mullerian malformations. Drop out criteria included no fresh embryo transfer, intolerance to GnRH-a, and nasal congestion during therapy. Patients were randomly assigned to either GnRH-a or a progesterone therapy.

Results:
The study cohort included 97 patients who underwent 106 cycles. A total of 83 cycles were included. Of them, 40 were treated with GnRH-a and 43 with progesterone. Significantly higher pregnancy rate was demonstrated in the GnRH-a group compared with the progesterone group (45% versus 23.3% p=0.034). OHSS rates were similar between the groups. After adjustment for age, BMI, past obstetric history, number of previous cycles, and other variables, GnRH-a was still associated with a higher pregnancy rate.

Conclusions:
This RCT suggests that GnRH-a for luteal phase support is associated with higher pregnancy rate, compared with standard progesterone support in an antagonist-based protocol triggered with hCG, while maintaining a similar safety profile.