Progesterone-modified natural cycle for frozen embryo transfer
Official title: Comparison of Progesterone-modified Natural Cycle and Hormone Replacement Therapy Cycle for Endometrial Preparation in Single Frozen Blastocyst Transfer
Run by Shandong University of Traditional Chinese Medicine · NCT06644794 · Data updated 2026-11-12
This tests whether a progesterone-modified natural cycle helps women aged 21–44 undergoing frozen embryo transfer have as good or better pregnancy and obstetric outcomes than standard hormone replacement therapy.
Quick facts
| Phase | Phase 3 |
|---|---|
| Study type | Interventional |
| Ages | 21 Years to 44 Years |
| Sex | Women only |
| Enrollment | 336 (estimated) |
| Sponsor | Shandong University of Traditional Chinese Medicine Academic / other |
| Locations | 1 site (Jinan, Shandong) |
| Status | Recruiting |
| Started | March 5, 2025 |
| Main results expected | September 10, 2027 |
| Study ends | December 1, 2028 |
| Registry record updated | April 29, 2026 |
| Trial ID | NCT06644794 on ClinicalTrials.gov |
Is this trial a fit for you?
✓Likely a good fit
Ideal candidates are women aged 21–44 with BMI 18–35 who have regular ovulatory cycles and are planning frozen embryo transfer.
✕Probably not a fit
Patients with untreated uterine adhesions, medical contraindications to estrogen or progesterone, conditions that preclude assisted reproduction or pregnancy, or a history of more than two implantation failures are unlikely to benefit or be eligible.
A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.
What this trial studies
This Phase 3 interventional trial directly compares two endometrial preparation methods for frozen-thawed embryo transfer: a progesterone-modified natural cycle (P4mNC) that preserves the corpus luteum and reduces monitoring visits, versus conventional hormone replacement therapy (HRT). Eligible participants (age 21–44, BMI 18–35, regular ovulatory cycles) will undergo FET prepared with one of the two protocols and key outcomes such as pregnancy rates and obstetric complications will be recorded. The P4mNC approach aims to combine physiologic benefits of a corpus luteum with greater patient convenience. The trial will test whether P4mNC maintains or improves perinatal safety and effectiveness compared with HRT.
Why it matters
Potential benefit: If successful, this approach could reduce obstetric complications and clinic visits while maintaining or improving pregnancy rates for women undergoing frozen embryo transfer.
How similar studies have gone: Smaller studies and observational data suggest natural-cycle transfers with a corpus luteum may lower some obstetric risks compared with HRT, but the progesterone-modified natural cycle has not been widely tested in large Phase 3 trials.
Who can join: the full rules
Show full inclusion / exclusion criteria
Inclusion Criteria: * Patients aged 21 to 44 years undergoing FBT * Body mass index (BMI) 18-35 kg/m2 * Having regular ovulatory cycles Exclusion Criteria: * Untreated uterine adhesions * Medical contraindications to estrogen and progesterone therapy * Illnesses contraindicating assisted reproductive technology or pregnancy * History of recurrent implantation failures (\> 2 embryo transfer failures)
Where it's running
-
Affiliated Hospital of Shandong University of Traditional Chinese Medicine
Jinan, Shandong, China Recruiting
Study contacts
- Principal investigator: Zhen-Gao Sun, MD — Affiliated Hospital of Shandong University of Traditional Chinese Medicine
- Study coordinator: Xian-Ling Cao, MD
- Email: caoxianlingling@163.com
- Phone: 0531-68901236
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How to take part
- Review the eligibility criteria above with your treating physician.
- Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
- Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.