Comparison of four protocols for luteal phase support in frozen-thawed Embryo transfer cycles: a randomized clinical trial.

Purpose To compare the pregnancy outcomes between four regimens of luteal phase support (LPS), including vaginal progesterone, oral dydrogesterone, combination of oral dydrogesterone and gonadotropin releasing hormone analog (GnRH-α), and combination of oral dydrogesterone and human chorionic gonadotrophin (hCG), in Frozen-thawed Embryo Transfer (FET) cycles.