Afsoon Zareii - Infertility Division, Infertility Research Center, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Sara Davoodi - Infertility Division, Infertility Research Center, Department of Obstetrics and Gynecology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Mahshid Alborzi - Infertility Division, School of Medicine, Jahrom University of Medical Sciences, Jahrom, Iran.
Marzieh Eslami Moghadam - School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.
Elham Askary - Department of Obstetrics and Gynecology, Laparoscopy Research Center, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran.

Background: Since progesterone alone does not seem to be enough for luteal phase support (LPS), especially in frozen embryo transfer (FET) cycles, so gonadotropin-releasing hormone agonist (GnRH-a) is suggested as an adjuvant therapy in combination with progesterone for LPS. Objective: To evaluate the effects of the administration of GnRH-a with vaginal progesterone compared to vaginal progesterone alone in luteal phase support of the frozen-thawed embryo transfer cycles. Materials and Methods: In this randomized controlled clinical trial, ۲۴۰ infertile women who were candidate for FET were evaluated into two groups (n = ۱۲۰/each). Group I received ۴۰۰ mg vaginal progesterone twice a day from the time of transfer. Second group received vaginal progesterone and also ۰.۱ mg diphereline on days ۰, ۳, and ۶ of FET for LPS. Finally, the clinical and ongoing pregnancy rates, and the implantation, and spontaneous abortion rates were compared in two groups. Results: Results showed that there was no significant difference between the mean age of women and the duration of infertility (p = ۰.۷۸, p = ۰.۵۸, respectively). There were no significant differences between groups in the terms of implantation and spontaneous abortion rates (p = ۰.۱۹, p = ۰.۳۱, respectively). However, in terms of clinical and ongoing pregnancy rates, the significant differences were seen between groups (p = ۰.۰۰۸ and p = ۰.۰۰۵, respectively). Conclusion: Co-administration of GnRH-a and vaginal progesterone in LPS may be superior to vaginal progesterone alone in women who underwent a frozen-selected embryo transfer cycle.

Luteal phase, Fertilization in Vitro, Embryo transfer., مرحله لوتئال, لقاح در شرایط آزمایشگاهی, انتقال جنین.