Received May 27, 2024
Accepted November 25, 2024

Objective: To compare the clinical outcomes, including pregnancy rate, live birth rate, and miscarriage rate between vaginal progesterone Cyclogest suppository and Crinone vaginal progesterone gel as LPS in frozen-thawed embryo transfer in Intra-Cytoplasmic Sperm Injection (ICSI) cycles. Methods: In this comparative retrospective study, 283 women who had frozen-thawed embryo transfer were reviewed. The patients were divided into two groups based on the route of progesterone administration used as LPS. When the endometrial thickness reached ≥ 8 mm, vaginal progesterone Cyclogest 400 mg/twice daily suppository was administered in one group; in another group, vaginal progesterone Crinone 8% 90 mg daily was administrated until a positive pregnancy test was confirmed. This was continued for 10�12 weeks after embryo transfer when fetal heart activity was detected by ultrasonography. Results: The patients� characteristics in the two groups were matched and there was no significant difference. The biochemical and clinical pregnancy, miscarriage, and live birth rates were similar�4.7% vs. 2.7%, p = 0.464; 26.1% vs. 23.3%, p = 0.638; 13.3% vs. 9.6%, p = 0.410; 15.6% vs. 16.4%, p = 0.872, respectively; there was no statistically significant difference between the vaginal progesterone Cyclogest group and the Crinone progesterone group. Conclusion: Clinical pregnancy, biochemical pregnancy, miscarriage, and live birth rates were similar between both groups. Moreover, vaginal progesterone Cyclogest and Crinone 8% gel are equally effective in providing support during the luteal phase for both blastocysts and cleavage-stage embryos in CET.