Impact Of FET Preparation Protocol On Endometrial Peristalsis: A Prospective Cohort Study

NCT07358468 | Recruiting

• 1 other identifier: 18/25/DD-BVMD
• Study Type: observational
• Target: 356
• Locations: 1 country
• Sites: 2

Brief Summary

The uterus is a dynamic muscular organ that undergoes rhythmic, wave-like contractions known as endometrial peristalsis or endometrial waves. This muscular activity, which is an essential component of natural fertility, presents a nuanced and sometimes contradictory role in the context of assisted reproductive treatments. Endometrial peristalsis refers to the frequency, amplitude, and pattern of myometrial contractions occurring in different reproductive phases. These peristalsis play vital roles in sperm transport, embryo migration, and implantation. Clinical and imaging studies suggest that abnormal patterns or excessive contractility at the time of embryo transfer may disrupt endometrial-embryo synchrony, impair implantation, and increase miscarriage risk. However, most evidence on endometrial peristalsis pertains to fresh embryo transfer cycles, natural conceptions, or pathological contexts, such as adenomyosis or fibroids, with limited insights regarding its effects on different endometrial preparation protocols in frozen embryo transfer (FET). Understanding the dynamics of endometrial peristalsis in this context is clinically important, as inappropriate contractile activity could physically expel the embryo or create a non-receptive environment, ultimately reducing the chances of live birth. Despite its theoretical significance, there is a paucity of robust, prospective data correlating endometrial peristalsis patterns measured around the time of FET with different endometrial preparation protocols with subsequent pregnancy outcomes.

Conditions

Infertility; Endometrial Peristalsis; Uterine Contraction; Endometrial Waves; Frozen Embryo Transfer (FET); Uterine Peristalsis

Keywords

endometrial peristalsis; uterine contractions; endometrial waves; frozen embryo transfer; natural cycles; artificial cycles

Outcome Measures

Primary Outcomes (1)

• The frequency of endometrial peristalsis at different time points, and different FET protocol.

  Frequency is defined as the number of peristaltic waves per minute.

  • On the second day to the fourth day of the menstrual cycle in the FET cycles. • The day of progesterone initiation or LH surge/hCG trigger, (before progesterone exposure) • On the day of embryo transfer, immediately prior to the procedure

Secondary Outcomes (26)

• Direction of peristalsis.

  • On the second day to the fourth day of the menstrual cycle in the FET cycles. • The day of progesterone initiation or LH surge/hCG trigger, (before progesterone exposure) • On the day of embryo transfer, immediately prior to the procedure

• The association between endometrial peristalsis at different time points and pregnancy rates

  Up to delivery

• The correlation between endometrial peristalsis at different time points

  • On the second day to the fourth day of the menstrual cycle in the FET cycles. • The day of progesterone initiation or LH surge/hCG trigger, (before progesterone exposure) • On the day of embryo transfer, immediately prior to the procedure

• Live birth rates after the one embryo transfer.

  At delivery

• Positive pregnancy test

  10-14 days after embryo transfer

Study Arms (2)

Exogenous steroid protocol

The endometrium was prepared with the use of oral estradiol valerate (Progynova®; Delpharm Lille SAS, France, or Valiera®, Laboratorios Recalcine) at a dose of 6 mg per day, starting on the second, third, or fourth day of the menstrual cycle. Endometrial thickness was monitored from day 10 onward, and vaginal progesterone (Cyclogest, LD Collins, UK) at a dose of 800 mg per day and dydrogesterone (Duphaston, Abbott Biologicals B.V, US) at a dose of 20 mg per day were started when the endometrial thickness reached 8 mm or more. Embryo transfer was performed at 4 days for cleavage embryos transfer or 6 days for blastocyst embryo transfer after starting progesterone. All embryos were warmed on the day of transfer. Vaginal progesterone administration will be maintained until the day of the pregnancy test. In the event of a positive test result, luteal phase support will be extended until 10 weeks of gestation.

Other: Endometrial peristalsis and hormone measurements

Natural protocol (True natural cycle or modified natural cycle)

Daily ultrasound and serum estradiol and LH level evaluation will be performed when the mean diameter of the dominant follicle of ≥14 mm. On natural cycle, LH surge initiation is defined as a concentration of 180% above the latest serum value available in that patient with a continued rise thereafter to a level of 20 IU/l or more detected by the ECLIA method (Roche Cobas® E 801, Roche Diagnostics, Germany). On modified natural cycle, when the mean diameter of the dominant follicle is ≥16 mm, human chorionic gonadotropin (hCG, Ovitrelle® 250 µg; Merck, USA) will be injected to trigger ovulation. Vaginal progesterone (Cyclogest, LD Collins, UK) at a dose of 800 mg per day was started 2 days after the LH surge/ hCG injection. Embryo transfer will be scheduled by the time of the initiation of LH and embryo stages. Vaginal progesterone administration will be maintained until the day of the pregnancy test. In the event of a positive test result, luteal phase

Other: Endometrial peristalsis and hormone measurements

Interventions

Endometrial peristalsis and hormone measurements OTHER

Time point for measurement Endometrial peristalsis will be assessed at three specific time points: * On the second day to the fourth day of the menstrual cycle in the FET cycles. * The day of progesterone initiation or LH surge/hCG trigger, (before progesterone exposure) * On the day of embryo transfer, immediately prior to the procedure Hormone measurements Serum levels of estradiol (E2) and progesterone (P4) will be assessed three times, on the same days as the endometrial peristalsis measurements, using electrochemiluminescence immunoassays. (Elecsys® Estradiol III and Elecsys® Progesterone III, Cobas® e 411, Roche Diagnostics, Germany): * On the second day to the fourth day of the menstrual cycle in the FET cycles * The day of progesterone initiation or LH surge/hCG trigger * On the transfer day prior to the procedure.

Exogenous steroid protocol; Natural protocol (True natural cycle or modified natural cycle)

Eligibility Criteria

• Age: 18 Years - 42 Years
• Healthy Volunteers: No
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

Women undergoing frozen embryo transfer during the study period.

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Mỹ Đức Hospital: lead
• My Duc Phu Nhuan Hospital HCMC, Vietnam: collaborator

Study Sites (2)

My Duc Phu Nhuan Hospital

Ho Chi Minh City, 70000, Vietnam

RECRUITING

IVFMD Phu Nhuan - My Duc Phu Nhuan Hospital

Ho Chi Minh City, Vietnam

NOT YET RECRUITING

MeSH Terms

Conditions

Infertility

Condition Hierarchy (Ancestors)

Genital Diseases; Urogenital Diseases

Study Officials

• Lan N Vuong, MD, PhD

  IVFMD and HOPE Research Center, My Duc Hospital

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Xuyen Thi Ha Le, MD

CONTACT

+84945260494; bsxuyen.lth@myduchospital.vn

Tuong M Ho, MD

CONTACT

+84903633377; tuongho.ivfmd@gmail.com

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 26, 2025
• First Posted: January 22, 2026
• Study Start: February 22, 2026
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2027
• Last Updated: March 18, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

VN (2)