Progesterone-modified natural cycle preparation for frozen embryo transfer

Area of Science:

• Reproductive Endocrinology
• In Vitro Fertilization

Background:

• Endometrial preparation is crucial for successful frozen embryo transfer (FET).
• Hormone replacement therapy (HRT) is a common protocol, but progesterone-modified natural cycle (P4mNC) offers an alternative.

Purpose of the Study:

• To compare clinical outcomes between P4mNC and HRT endometrial preparation protocols in single euploid blastocyst FET cycles.
• To evaluate live birth rate, clinical pregnancy rate, and miscarriage rate.

Main Methods:

• Retrospective cohort study of 723 FET cycles (January 2017-December 2019).
• Comparison of 327 P4mNC-FET cycles and 396 HRT-FET cycles.
• Analysis of primary (live birth rate) and secondary (clinical pregnancy, miscarriage rates) outcomes.

Main Results:

• No statistically significant differences were observed in live birth rates (45.0% vs. 39.6%, P=0.331).
• Clinical pregnancy rates (50.2% vs. 47.0%, P=0.688) and miscarriage rates (9.8% vs. 14.5%, P=0.115) were also comparable between groups after adjustments.

Conclusions:

• P4mNC-FET cycles yield clinical outcomes similar to HRT-FET cycles.
• P4mNC provides a viable alternative to HRT, offering comparable efficacy with enhanced flexibility in FET timing.