Natural Versus Artificial Cycle for Frozen-Thawed Embryo Transfer (NAFT)

February 25, 2025 updated by: Universitaire Ziekenhuizen KU Leuven

Frozen-thawed Embryo Transfer in a Natural Versus Artificial Cycle: a Randomized Clinical Trial

This study evaluates clinical pregnancy rates, obstetrical outcome parameters, costs and patient preferences in natural cycle versus artificial cycle frozen embryo transfers (FET).

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Transfer of cryopreserved embryos can be performed in a natural cycle (NC-FET) or in an artificially prepared cycle (AC-FET). Both cycle regimens have their advantages and disadvantages. So far, most comparative studies have failed to identify the optimal protocol for FET. In this study patients undergoing FET will be randomized between an endometrial preparation by a natural cycle or by an artificial cycle (by oestradiol validate and micronized progesterone).

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
554

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Phase 4

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Belgium
      • Leuven, Belgium, 3000
        • UZ Leuven

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 45 years (Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Women undergoing FET after a first, second or third fresh IVF/ICSI cycle
  • Single embryo transfer (SET) or Double embryo transfer (DET)
  • Female age between 18-45 year
  • Women having a natural ovulatory cycle (24-35 days)
  • Normal uterine cavity (fundal indentation at the cavity <10mm)
  • Written informed consent

Exclusion Criteria:

  • Use of donor gametes
  • BMI > or equal to 35 kg / m2
  • Any contra-indication to estrogen or progesterone supplementation (e.g. history of thrombosis, prior or current hormone-sensitive malignancy…)

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Natural cycle
no medication
Drug: Natural cycle
no medication
Active Comparator: Artificial cycle

Oestradiol valerate (Progynova, Bayer, Germany) 6mg daily will be given from day 2 of the cycle. The dose of Progynova is increased to 8mg daily if the endometrial thickness is less than 7mm after 7-10 days of Progynova use. Progynova will be discontinued the day of the pregnancy test in case of a negative result. In case of a pregnancy, Progynova will be continued until 12 weeks or until diagnosis of a non-viable pregnancy.

Micronized progesterone (Utrogestan, Besins, Belgium) 200 mg vaginally three times daily is started as soon as the endometrial thickness is 7 mm. Utrogestan will be discontinued the day of the pregnancy test in case of a negative result. In case of a pregnancy, Utrogestan will be continued until 12 weeks or until diagnosis of a non-viable pregnancy.
Drug: Estradiol Valerate
Oestradiol valerate (Progynova, Bayer, Germany) 6mg daily will be given from day 2 of the cycle. The dose of Progynova is increased to 8mg daily if the endometrial thickness is less than 7mm after 7-10 days of Progynova use. Progynova will be discontinued the day of the pregnancy test in case of a negative result. In case of a pregnancy, Progynova will be continued until 12 weeks or until diagnosis of a non-viable pregnancy.
Other Names:
  • Artificial cycle
Drug: Micronized progesterone
Micronized progesterone (Utrogestan, Besins, Belgium) 200 mg vaginally three times daily is started as soon as the endometrial thickness is 7 mm. Utrogestan will be discontinued the day of the pregnancy test in case of a negative result. In case of a pregnancy, Utrogestan will be continued until 12 weeks or until diagnosis of a non-viable pregnancy.
Other Names:
  • Artificial cycle

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Clinical pregnancy rate with fetal heart beat
Time Frame: 9 weeks
Clinical pregnancy rate with fetal heart beat diagnosed by ultrasound no later than the gestational age of 9 weeks
9 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Biochemical pregnancy rate
Time Frame: 9 weeks
9 weeks
Miscarriage rate
Time Frame: 12 weeks
12 weeks
Ectopic pregnancy rate
Time Frame: 9 weeks
9 weeks
Live birth rate
Time Frame: 41 weeks
41 weeks
Multiple pregnancy rate
Time Frame: 9 weeks
9 weeks
Adverse events
Time Frame: 12 weeks
tombo-embolic events, serious side-effects (car leaflet) which require cancellation of treatment
12 weeks
Cycle cancellation rate
Time Frame: 4 weeks
4 weeks
Endometrial thickness
Time Frame: 3 weeks
3 weeks
Endometrial pattern
Time Frame: 3 weeks
Sonographic aspect of the endometrium (triple-line, no triple-line)
3 weeks
number of center visits to monitor FET cycle
Time Frame: From date of randomization until the date of the embryo transfer or until cancellation (estimated period of time up to 4 weeks)
From date of randomization until the date of the embryo transfer or until cancellation (estimated period of time up to 4 weeks)
cost analysis per treatment cycle
Time Frame: From date of randomization until the date of the embryo transfer or until cancellation (estimated period of time up to 4 weeks)
From date of randomization until the date of the embryo transfer or until cancellation (estimated period of time up to 4 weeks)
patient satisfaction
Time Frame: 12 weeks
To evaluate the effect of the different regimens on patients wellbeing/distress, Patient Reported Experience Measures (PREMS) from validated questionnaires will be used. Twenty-two questions from the Benyamini questionnaire will be used (Benyamini et al. 2005) and 10 questions from the subscales 'environment' (α=0.81) and 'tolerability' (α=0.75) of the FertilQol questionnaire (Pedro et al 2013). On the day of embryo transfer, the treating gynecologist will hand out the questionnaire to the patient. The patient will return the filled-in questionnaire on the day of the pregnancy test, before she knows the result of the pregnancy test.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Universitaire Ziekenhuizen KU Leuven

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Jessa Hospital
Imelda Hospital, Bonheiden
GZA Ziekenhuizen Campus Sint-Augustinus

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
September 25, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
November 1, 2024

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
November 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
July 17, 2018

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
August 20, 2018

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
August 22, 2018

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
March 25, 2025

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 25, 2025

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2024

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • S61372

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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