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

NCT06053827 | Completed

• 1 other identifier: 3356
• Study Type: observational
• Target: 1,207
• Locations: 1 country
• Sites: 1

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

Outcome Measures

Primary Outcomes (1)

• Evaluate the clinical pregnancy rate of embryo transfer in natural vs substituted cycles

  clinical pregnancy is the presence of fetal heartbeat at the viability ultrasound

  6 to 8 weeks after Frozen Embryo Transfer

Study Arms (2)

Frozen embryo transfer substituted cycle

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

Other: Frozen embryo transfer

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

Other: Frozen embryo transfer

Interventions

Frozen embryo transfer 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; Frozen embryo transfer substituted cycle

Eligibility Criteria

• Age: Up to 40 Years
• Gender Eligibility Details: Women able to have an embryo transfered in their uterus
• Age Groups: Child (0-17), Adult (18-64)
• Sampling Method: Probability Sample

Study Population

Data spreadsheet from Jan 2022 to March 2023 of patients undergoing natural or substituted frozen embryo transfer

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Clinique Ovo: lead

Study Sites (1)

Clinique Ovo

Montreal, Quebec, H4P 2S4, Canada

Location

Study Officials

• Camille Sylvestre, MD

  clinique ovo R&D department

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: RETROSPECTIVE
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 19, 2023
• First Posted: September 26, 2023
• Study Start: September 19, 2023
• Primary Completion: November 30, 2023
• Study Completion: July 18, 2024
• Last Updated: December 9, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

CA (1)