Fertility DisordersNCT06053827
Natural Frozen Embryo Transfer (FET) vs Substituted Frozen Embryo Transfer (FET)
An observational study of Fertility Disorders, run by Clinique Ovo at 1 site in Canada.
Trial 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. Read more about this study
- Who is it for?
- Ages Up to 40 years, women only
- Conditions the study is for
- Fertility Disorders
- What is being tested?
- Frozen embryo transfer
- How many people
- 1,207 participants
- Where
- 1 siteCanada
- Study dates
- 19 Sep 2023to 18 Jul 2024
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Up to 40 years
- Women only
- Child, Adult
Study population: Data spreadsheet from Jan 2022 to March 2023 of patients undergoing natural or substituted frozen embryo transfer
Who may be able to join
- 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
Who cannot join
- 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
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Embryo Transfer in Natural vs Substituted Cycle and the Scheduling Pattern of IVF
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
- Being tested
- Frozen embryo transfer
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Frozen embryo transferOther
A frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy
| Study group | Role | What they receive |
|---|---|---|
| Frozen embryo transfer substituted cycle | In a substituted cycle, estrogen and progesterone are given and a transfer is planned when the endometrium is ready Receives: 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 Receives: Other: Frozen embryo transfer |
What is being measured
The primary outcome is the main question the study is designed to answer.
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
Measured: 6 to 8 weeks after Frozen Embryo Transfer
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 Sep 2023
- Study start19 Sep 2023
- Primary completion30 Nov 2023
- Study completion18 Jul 2024
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Fertility DisordersStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Retrospective
- Enrolment
- 1,207 participants (actual)
Sponsor and investigators
- Lead sponsor
- Clinique Ovo
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
- Investigators
- Camille Sylvestre, MD, Principal investigator, clinique ovo R&D department
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06053827
- Sponsor's protocol ID
- 3356
- Status last verified
- Dec 2025
- First submitted
- 19 Sep 2023
- Last updated
- 9 Dec 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 9 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Embryo Transfer in Natural vs Substituted Cycle and the Scheduling Pattern of IVF
- ClinicalTrials.gov ID
- NCT06053827
- Acronym / sponsor ID
- 3356
- Conditions
- Fertility Disorders
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 1,207 participants (actual)
- Lead sponsor
- Clinique OvoIndustry (pharma, biotech, devices)
- Study start
- 19 Sep 2023 (actual)
- Primary completion
- 30 Nov 2023 (actual)
- Study completion
- 18 Jul 2024 (actual)
- First posted
- 26 Sep 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Study design
- Observational model
- Cohort
- Time perspective
- Retrospective
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Frozen embryo transfer substituted cycle | – | Other: Frozen embryo transferIn a substituted cycle, estrogen and progesterone are given and a transfer is planned when the endometrium is ready |
| Frozen embryo transfer natural cycle | – | Other: Frozen embryo transferIn a natural cycle no hormones are given and a transfer is planned when there is a dominant follicle apparent at the ultrasound |
Who may qualify
- Ages
- Up to 40 years
- Sex
- Female only
- Age groups
- Child, Adult
- Study population
- Data spreadsheet from Jan 2022 to March 2023 of patients undergoing natural or substituted frozen embryo transfer
Key inclusion criteria (3 listed)
- 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
Key exclusion criteria (7 listed)
- 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
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Frozen embryo transferA frozen embryo transfer involves thawing a fertilized embryo and transferring it in the uterus in order to obtain a pregnancy | Other | Frozen embryo transfer natural cycle, Frozen embryo transfer substituted cycle |
Primary outcome
Evaluate the clinical pregnancy rate of embryo transfer in natural vs substituted cycles
Time frame: 6 to 8 weeks after Frozen Embryo Transfer
clinical pregnancy is the presence of fetal heartbeat at the viability ultrasound
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 9 Dec 2025.
- Individual participant dataSharing planned: No
Related trials for Fertility Disorders
Active, not recruiting
Ovarian Tissue Cryopreservation in Children
Cancer
Not yet recruiting
Sperm, Exposure and Endocrine Disruptors
Fertility, Male Fertility
Recruiting
Dietary Intervention to Improve Fertility in Women With Endometriosis Undergoing IVF
Endometriosis
RecruitingObservational study
Gonadal Tissue Freezing for Fertility Preservation in Individuals at Risk for Ovarian Dysfunction, Premature Ovarian Insufficiency and Clinically Indicated Gonadectomy
Turner Syndrome, Post-menarcheal Adolescents
Active, not recruitingObservational study
Factors Influencing Fertility or Pregnancy Health
Menstrual Cycles, Conception
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Camille Sylvestre, MD principal investigator
clinique ovo R&D department
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Fertility Disorders, run by Clinique Ovo at 1 site in Canada.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 7 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 9 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Canada. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Evaluate the clinical pregnancy rate of embryo transfer in natural vs substituted cycles (time frame: 6 to 8 weeks after Frozen Embryo Transfer). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 9 Dec 2025.