How frozen embryo transfer preparation affects uterine wave activity

Effects Of Endometrial Preparation Protocols On Peristalsis And Pregnancy Rates In Frozen Embryo Transfer: A Prospective Cohort Study

Observational Mỹ Đức Hospital · NCT07358468

We will test whether preparing for frozen embryo transfer with hormones or using a natural cycle changes uterine contractions in women having FET.

Quick facts

Study typeObservational
Enrollment356 (estimated)
Ages18 Years to 42 Years
SexFemale
SponsorMỹ Đức Hospital Academic / other
Locations2 sites (Ho Chi Minh City and 1 other locations)
Trial IDNCT07358468 on ClinicalTrials.gov

What this trial studies

This is a prospective observational cohort comparing hormone replacement therapy (HRT) protocols versus true or modified natural cycles in patients undergoing frozen embryo transfer. Investigators will measure endometrial peristalsis (uterine wave frequency, amplitude, and pattern) by imaging around the time of transfer and record concurrent hormone levels. The study will correlate peristalsis characteristics with implantation and early pregnancy outcomes without altering participants' planned treatment. Data collection is limited to patients treated at the participating center and follows standard clinical FET procedures.

Who should consider this trial

Good fit: Women age 18–42 scheduled for frozen embryo transfer using either hormone replacement therapy or a true/modified natural cycle, transferring up to two cleavage embryos or one good-quality blastocyst, are ideal candidates.

Not a fit: Patients with untreated uterine abnormalities, PCOS, cycles involving oocyte donation or preimplantation genetic testing, or those requiring uterine relaxants would likely not benefit from this study's findings.

Why it matters

Potential benefit: If successful, the findings could help clinicians choose FET preparation methods that reduce disruptive uterine contractions and improve chances of implantation and pregnancy.

How similar studies have performed: Prior research in fresh IVF cycles has linked lower endometrial peristalsis to higher pregnancy and live birth rates, but direct comparisons of different FET preparation protocols are limited.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Women aged 18 - 42 years old
* Scheduled for frozen embryo transfer cycles using hormone replacement therapy protocol or natural cycle protocol (True natural cycles or modified natural cycles)
* Transferred no more than two cleavage embryos or one good-quality blastocyst or no more than two poor-quality blastocysts

Exclusion Criteria:

* Having an allergy and contraindications for exogenous hormone administration (e.g., breast cancer, thromboembolic disease)
* Cycles with preimplantation genetic testing, oocyte donation, or in vitro maturation
* Having untreated uterine or adnexal abnormalities (e.g., intrauterine adhesions, unicornuate/ bicornuate/ arcuate uterus, endometrial polyp, large leiomyoma ≥5 cm in diameter, hydrosalpinx, endometrial hyperplasia).
* Use of uterine relaxants or intralipid infusion during the embryo transfer process.
* Use of a GnRH-agonist for downregulation within one month.
* PCOS patients

Where this trial is running

Ho Chi Minh City and 1 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions InfertilityEndometrial PeristalsisUterine ContractionEndometrial WavesFrozen Embryo TransferUterine Peristalsisendometrial peristalsisuterine contractions
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.