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

Sponsor
Mỹ Đức Hospital
Study ID
NCT07358468
Status
Recruiting
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Conditions

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

Eligibility Criteria

Sex
FEMALE
Age
18 Years - 42 Years
Healthy Volunteers
Not accepted

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.

Study Details

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.

Key Dates

First listed
Jan 22, 2026
Start date
Feb 22, 2026
Status verified
Mar 2026
Primary completion
Dec 1, 2026
Completion
Dec 1, 2027

Study Design

Enrollment
356 participants (estimated)

Arms

  • Arm: 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.
  • Arm: 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

Primary Outcome Measure

The frequency of endometrial peristalsis at different time points, and different FET protocol. [ Time Frame: • 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 ]

Central Contacts

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