Luteal phase support for assisted reproductive technologies: between past, present and future

Area of Science:

• Reproductive Endocrinology
• Assisted Reproductive Technologies

Background:

• The luteal phase is critical for pregnancy establishment, occurring between ovulation and either conception or menstruation.
• Assisted reproductive technologies (ART), particularly controlled ovarian stimulation (COS), can disrupt normal luteal phase regulation.
• Current therapeutic strategies for luteal phase support (LPS) in ART cycles lack universal consensus.

Purpose of the Study:

• To review current practices and ongoing research regarding luteal phase support (LPS) in assisted reproductive technology (ART) cycles.
• To evaluate the effectiveness and controversies surrounding different luteal phase support protocols, including progesterone, hCG, and GnRH agonists.
• To discuss the established use of vaginal progesterone as first-line therapy and the ongoing debate on its optimal administration.

Main Methods:

• Review of existing literature and clinical studies on luteal phase support in ART.
• Analysis of progesterone-based protocols versus alternative regimens like human chorionic gonadotropin (hCG) and GnRH agonists (GnRH-a).
• Examination of emerging research on GnRH agonists for ovulation triggering and subsequent luteal phase support.

Main Results:

• Progesterone-based protocols are the most common for LPS in ART, with vaginal progesterone now considered first-line therapy.
• The use of GnRH agonists (GnRH-a) for ovulation triggering is being increasingly studied for its impact on luteal phase support.
• Debate continues regarding the optimal timing and duration of luteal phase supplementation, even after pregnancy confirmation.

Conclusions:

• While vaginal progesterone is the current standard for luteal phase support in ART, optimal protocols require further investigation.
• The role of GnRH agonists in ovulation triggering and their impact on luteal phase support efficacy warrants continued research.
• Despite limited evidence, progesterone supplementation is widely used in intrauterine insemination cycles for luteal phase support.