Optimal Duration of Progesterone Treatment before Cryopreserved-Thawed Embryo Transfer

Objective: To investigate the optimal duration of progesterone therapy before cryopreserved-thawed embryo transfer and its impact on clinical pregnancy and live birth rates. Methods: Five hundreds women undergoing cryopreserved-thawed embryo transfer were included in the study. These patients had a total of 500 embryos frozen on day 3 (n = 200), day 4 (n = 100), day 5 (n = 150) and day 6 (n = 50). Artificial endometrial preparation was successfully performed in all participants. If the endometrial thickness reached a minimum of 8 mm or in the presence of a triple-line view, the patients were divided into four different groups and each group into two subgroups according to the estimated duration of progesterone treatment to be used. Group 1 (n = 200): This group consisted of patients with day 3 embryo transfer. While 100 of 200 patients received embryo transfer after 3 days of progesterone treatment, the remaining 100 patients received embryo transfer after 4 days of progesterone treatment. Group 2 (n = 100): This group consisted of patients who underwent day 4 embryo transfer. While 50 of 100 patients had embryo transfer after 4 days of progesterone treatment, the remaining 50 patients received embryo transfer after 5 days of progesterone treatment. Group 3 (n = 150): This group consisted of patients who received day 5 embryo transfer. While 75 of 150 patients received embryo transfer after 5 days of progesterone treatment, the remaining 75 patients received embryo transfer after 6 days of progesterone treatment. Group 4 (n = 50): While 25 of 50 patients received embryo transfer after 6 days of progesterone treatment, the remaining 25 patients received embryo transfer after 7 days of progesterone treatment. The primary outcome measure of our study was to evaluate clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), live birth rate (LBR) and miscarriage rate per pregnancy. Results: Clinical pregnancy rates were found in 50 of 100 (50%) cases who were given progesterone for 3 days. Of the 100 cases who were given progesterone for 4 days, 40 clinical pregnancy was detected (40%). Both OPR and LBR were found to be significantly lower in patients who received 4 days of progesterone treatment compared to those given 3 days. The rates of miscarraige (9.09%) in patients who received progesterone treatment for 4 days were significantly higher than those who received progesterone for 3 days (5.8%). In Group 2 both OPR and LBR were found to be significantly lower in patients who received 5 days of progesterone treatment compared to those given 4 days. The rate of miscarraige (25.0%) was significantly higher in patients who received progesterone treatment for 5 days compared to those who received progesterone for 4 days (33.3%). When 75 patients in group III who underwent embryo transfer on the fifth day and received progesterone treatment for 5 days and 75 patients who were given progesterone treatment for 6 days were evaluated in terms of CPR, OPR and LBR the difference was statistically significant between the two gruops. When patients in group IV were evaluated in terms of CPR, OPR and LBR the difference was statistically insignificant. Conclusions: Extending the progestereone usage period one day before embryo transfer has been found beneficial in patients who have been transferred for only fifth day.