Natural Cycle Versus Hormone Replacement Therapy Cycle for a Frozen-thawed Embryo Transfer in PGT Patients

Summary

The aim of the current study is to compare miscarriage rates (before 8 weeks) between a true natural cycle (awaiting spontaneous LH surge) and a hormone replacement therapy cycle prior to blastocyst transfer in preimplantation genetic testing (PGT) patients, with biopsy on day 5 of embryonic development. The advantage of performing the study in PGT patients is the exclusion of aneuploidy as a cause of miscarriage.

Timeline

Start

2019-05-25

Primary completion

2025-01-01

Completion

2025-01-01

Outcome

Met primary endpoint

Stopped: “safety”

paper In the intention-to-treat analysis, EPL per started FET cycle occurred in 6.7% of patients in the NC-FET group and 14.2% in the AC-FET group (P = 0.022). PMID 42081915 ↗

Publications

• Roelens C, Santos-Ribeiro S, Mackens S, De Vos A, Keymolen K, Verdyck P, De Vos M, Tournaye H, Verpoest W, Blockeel C. The impact of endometrial preparation on pregnancy loss in vitrified-warmed euploid blastocyst transfer cycles: a randomized controlled trial. Hum Reprod. 2026 Jun 1;41(6):910-917. doi: 10.1093/humrep/deag060.

Drugs

Evaluation	Drug	Modality	Dose	Route
Subject	Micronized progesterone	Unknown	200 mg	—
Subject	estradiol valerate	Unknown	2 mg	—

Indications