A randomized controlled trial of vaginal progesterone for luteal phase support in modified natural cycle - frozen embryo transfer.

Our aim was to study whether luteal phase support (LPS) increases the live-birth rate (LBR) in women undergoing modified natural cycle (mNC) frozen-thawed embryo transfer (FET). In a randomized controlled trial, conducted at a university-affiliated tertiary medical center, a total of 59 patients aged 18-45 years, underwent mNC-FET. FET was performed in mNC following ovulation triggering by hCG. Patients were randomized into two groups; The No-LPS Group included 28 women who did not receive LPS, and the LPS Group included 31 women who received vaginal progesterone for LPS. The main outcome measure was LBR. Baseline demographic and clinical characteristics were comparable between the study groups. The no-LPS group and the LPS group did not differ with regard to clinical pregnancy rate (21.4% vs. 32.3%; respectively, The results of our study suggest that LPS after mNC-FET does not improve the reproductive outcome, and therefore, might not be necessary.