Natural Frozen Embryo Transfer (FET) vs Substituted Frozen Embryo Transfer (FET)

NCT ID: NCT06053827

Last Updated: 2025-12-09

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 1207 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2023-09-19
• Study Completion Date: 2024-07-18

Brief Summary

In frozen embryo transfer substituted cycles, patients are treated with progesterone and estrogen in an attempt to mimic the natural cycle and a transfer is planned whenever the endometrium is ready. In contrast, in frozen embryo transfer natural cycle patients are not taking any hormones, only triggered with hCG (human chorionic gonadotropin) when a dominant follicle is ready or they wait for the disappearance of the dominant follicle to plan the transfer date. Some doctors and centres shift towards using the substituted protocol in an attempt to make scheduling easier with less frequent ultrasounds.

This study will aim to compare clinical and biochemical pregnancy rates in patients who underwent frozen embryo transfers in natural cycles vs substituted cycles at the centre.

Conditions

Fertility Disorders

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: RETROSPECTIVE

Study Groups

Frozen embryo transfer substituted cycle

In a substituted cycle, estrogen and progesterone are given and a transfer is planned when the endometrium is ready

Frozen embryo transfer

Intervention Type: OTHER

A frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy

Frozen embryo transfer natural cycle

In a natural cycle no hormones are given and a transfer is planned when there is a dominant follicle apparent at the ultrasound

Frozen embryo transfer

Intervention Type: OTHER

A frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy

Interventions

Frozen embryo transfer

A frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy

Intervention Type: OTHER

Eligibility Criteria

Inclusion Criteria

• Age < 40 years old
• Women having undergone either a frozen embryo transfer in natural cycle or substituted cycle
• IVF and FET cycles done at Clinique OVO

Exclusion Criteria

• egg or embryo recipient
• History of recurrent miscarriages, defined as ≥ 3 consecutive losses
• Patients that needed Viagra, Plasma-Rich Platelet (PRP) or other modalities to improve their endometrial thickness
• Uterine abnormalities
• Abnormal hormonal profiles
• FET Stimulated cycles
• History of recurrent implantation failure defined as failed ≥ 2 euploid embryos transfer or ≥ 3 blastocysts

• Maximum Eligible Age: 40 Years
• Eligible Sex: FEMALE
• Accepts Healthy Volunteers: No

Sponsors

Clinique Ovo

INDUSTRY

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Camille Sylvestre, MD

Role: PRINCIPAL_INVESTIGATOR

clinique ovo R&D department

Locations

Clinique Ovo

Montreal, Quebec, Canada

Countries

Canada

Other Identifiers

3356

Identifier Type: -

Identifier Source: org_study_id