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.

Methods: This randomized clinical trial was performed during a 6-month period, including candidates for FET. Patients were randomly assigned to four groups for LPS: 400 mg vaginal progesterone suppository twice daily, 10 mg oral dydrogesterone twice daily, 10 mg oral dydrogesterone twice daily combined with injection of 0.1 mg GnRH-α, and 10 mg oral dydrogesterone twice daily combined with injection of 1500 IU hCG. Primary endpoint included clinical pregnancy rate, ongoing pregnancy rate (OPR), and miscarriage rate (MR).

Results: A total of 400 FET cycles were analyzed. CPR was significantly lower in dydrogesterone group (9 %) when compared to vaginal progesterone (20 %), dydrogesterone and GnRH-α (25 %), and dydrogesterone and hCG (17 %). Logistic regression showed that only dydrogesterone group had significantly lower CPR in comparison with vaginal progesterone (OR = 0.39; p = 0.03), while it was comparable between other three groups. There were no significant difference between four groups regarding to OPR and MR.

Conclusion: Vaginal progesterone provides appropriate LPS. Yet, combination of oral dydrogesterone and GnRH-α or hCG can be more suitable option compared to vaginal progesterone for LPS in women with vaginal irritation or discharge at a lower cost.