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Immediate Versus Delayed Natural Cycle Frozen Embryo Transfers

NCT05215119 · Status: COMPLETED · Type: OBSERVATIONAL · Enrollment: 818

Last updated 2025-02-11

No results posted yet for this study

Summary

Introduction:

Based on recent studies the suggestion is that natural cycle frozen embryo transfers (NC FET) should preferably be used, with evidence suggesting that artificial cycle FET (AC FET) is subject to increased risks of adverse obstetric and perinatal outcomes and possibly lower live birth rates. There, however, is limited evidence on the most efficient and effective timing of NC FET following oocyte retrieval.

Objective: In this non-inferiority randomised controlled trial, the effect on reproductive outcomes of NC FET performed immediately following the oocyte retrieval cycle (i.e., after one menstruation) will be investigated.

Materials and Methods: At a single IVF centre, patients will be recruited from infertile patients presenting for freeze-all-IVF treatments. Patients aged 18 to 30 years will be enrolled, if they had ≤2 previous embryo transfers and had ≥1 blastocyst cryopreserved in their freeze-all cycles. Enrolled patients (N = 800) will be randomised (1:1) to either the immediate group (i.e., FET performed in the menstrual cycle immediately following the oocyte retrieval cycle) or the delayed group (i.e., FET performed in the menstrual cycle following two menstruations). All FET will be performed in NC. The primary outcome measure will be clinical pregnancy, defined as the visual confirmation by transvaginal ultrasound scan of a gestational sac with normal heartbeat at \>5 weeks of gestation. The analyses will be performed according to per-procedure principles.

Results: The ovarian, endometrial and time to transfer outcomes of the immediate group will be compared with those of the delayed group. The clinical pregnancy rate of the immediate group will be compared with that of the delayed group.

Conditions

  • Clinical Pregnancy

Interventions

PROCEDURE

natural cycle endometrial preparation

Cycles will be monitored from either day-10 or-12, according to patient's menstrual cycle length, with serial analysis of blood serum LH and progesterone levels and assessment of dominant follicle growth. In a spontaneous cycle, ovulation will be determined by a LH surge (\>20 IU/L) and a corresponding rise in progesterone (\>0.8 ng/ml). In a triggered cycle, ovulation will be determined by the administration of an hCG trigger when the dominate follicle reached \>16 mm (and LH was \<20 IU/L).

Sponsors & Collaborators

  • Antalya IVF

    lead OTHER

Eligibility

Min Age
18 Years
Max Age
40 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2022-03-04
Primary Completion
2025-02-08
Completion
2025-02-08

Countries

  • Turkey (Türkiye)

Study Locations

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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT05215119 on ClinicalTrials.gov