Objective: To determine whether a single dose of gonadotropin-releasing hormone (GnRH) agonist administered subcutaneously in addition to the regular progesterone supplementation could provide a better luteal support in antagonist protocol fresh embryo transfer cycles. Methods: This prospective, multicentric, cohort study included total 140 women, 70 in each group. Controlled ovarian stimulation was carried out as per fixed GnRH antagonist protocol. The trigger was given with hCG. In vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) was performed and day-3 embryos were transferred. Patients were divided into groups 1 and 2 based on computer generated randomization sheet. Six days following oocyte retrieval, group 1 received 0.2 mg decapeptyl subcutaneously in addition to regular progesterone support while group 2 received progesterone only. Luteal support was given for 14 days to both groups; if pregnancy was confirmed luteal support was continued till 12 weeks of gestation. The clinical pregnancy rate was the primary outcome. The implantation rate, miscarriage rate, live birth delivery rate, and multiple pregnancy rates were the secondary outcomes. Results: A total of 140 patients were analysed, 70 in each group. Clinical pregnancy rates (47.1% vs. 35.7%; P=0.17), implantation rates (23.4% vs. 18.1%, P=0.24), live birth delivery rates (41.4% vs. 27.1%, P=0.08), and multiple pregnancy rates (21.2% vs. 16.0%, P=0.74) were higher in group 1 than in group 2. Group 1 had a lower miscarriage rate than group 2 (5.7% vs. 8.6%; P=0.75). However, these differences were not statistically significant between the two groups. Conclusions: Administration of a single dose of GnRH agonist in addition to regular natural micronized vaginal progesterone as luteal support in GnRH antagonist protocol cycles marginally improves implantation rates, clinical pregnancy rates, and live birth delivery rates. However, more studies with higher sample sizes are needed before any conclusive statements about GnRH agonist as luteal phase support can be made.