Progesterone Supplementation After Letrozole-stimulated Insemination (LIFT)

March 27, 2026 updated by: Kirstine Kirkegaard

Luteal Phase Support Following Letrozole Treatment in Women Undergoing Intrauterine Insemination: a Multicenter Randomized Trial

This trial aims to investigate whether luteal phase support improves the chance of pregnancy in women undergoing intrauterine insemination (IUI) following ovarian stimulation with letrozole.

In this randomized clinical trial, 690 women undergoing letrozole-stimulated IUI at four public fertility clinics in Denmark will be randomly allocated to one of two groups:

  • Vaginal progesterone from the day after insemination (Cyclogest 400 mg twice daily)
  • No luteal phase support, reflecting current clinical practice

All participants will undergo a standard letrozole-stimulated IUI treatment, including ultrasound monitoring, ovulation triggering, and insemination. Blood samples will be collected on the day of insemination and 7-9 days after insemination to measure hormone levels.

The results of this trial will provide further insight into the role of progesterone support in letrozole-stimulated IUI cycles.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

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.

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 (Estimated)

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.
690

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 Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • Denmark
      • Copenhagen, Denmark, 2100
        • Copenhagen University Hospital - Rigshospitalet. Department of Gynecology, Fertility and Obstetrics
        • Contact:
        • Principal Investigator:
          • Kristine Løssl, Clinical Associate Professor
      • Herlev, Denmark, 2730
        • The Fertility Clinic, Herlev Hospital
        • Contact:
        • Principal Investigator:
          • Maria Birkvad Rasmussen, Clinical Associate Professor
      • Horsens, Denmark, 8700
        • University Clinic for Fertility, Horsens Regional Hospital, Central Denmark Region
        • Contact:
        • Principal Investigator:
          • Kirstine Kirkegaard, Clinical Associate Professor
      • Hvidovre, Denmark, 2650

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

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age 18-37 years
  • Scheduled for IUI with homologous or donor sperm
  • Undergoing mild ovarian stimulation with letrozole
  • Ability to provide written informed consent

Exclusion Criteria:

  • Age > 37 years
  • Anovulation due to hypogonadotropic hypogonadism
  • Known hypersensitivity to progesterone or hard fat listed as an excipient in the Summary of Product Characteristics (SmPC) for Cyclogest.
  • Known or suspected progesterone-sensitive malignant tumours
  • Porphyria
  • Known missed abortion or ectopic pregnancy
  • Active arterial or venous thromboembolism, severe thrombophlebitis, or a history of these conditions
  • Severe hepatic dysfunction or liver disease
  • Inability to speak or understand Danish sufficiently to comprehend oral and written study information

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: Single

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: Intervention
Vaginal progesterone luteal phase support. Progesterone is administered as Cyclogest 400 mg twice daily form the day after insemination. Treatment is continued until gestational age 10 weeks in the event of clinical pregnancy, or until pregnancy is ruled out in women who do not achieve a clinical pregnancy.
Drug: Progesterone
Vaginal progesterone (Cyclogest) 400 mg administered twice daily starting the day after insemination. Treatment is continued until gestational age 10 weeks in the event of clinical pregnancy or until clinical pregnancy is ruled out.
Other Names:
  • Cyclogest
No Intervention: Comparison
No luteal phase support will be administered after insemination, reflecting current standard treatment.

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
Time Frame: Gestational age 7-9 weeks
Defined as an ultrasonographically visible foetal heartbeat at 7-9 weeks of gestation
Gestational age 7-9 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
Live Birth Rate
Time Frame: At the time of delivery
Defined as the birth of one or more living infants after a pregnancy of GA ≥ 22 weeks
At the time of delivery
Biochemical Pregnancy Rate
Time Frame: 14-17 days after intrauterine insemination
Defined as a positive serum or urine β-hCG test 14-17 days after intrauterine insemination
14-17 days after intrauterine insemination
Early Pregnancy Loss
Time Frame: Up to 10 weeks of gestation
Defined as intrauterine pregnancy loss before 10 weeks of gestational age
Up to 10 weeks of gestation
Fetal miscarriage
Time Frame: From 10 weeks of gestation to delivery
Defined as pregnancy loss ≥ 10 weeks size with a fetus (≥ 33 mm) on ultrasound
From 10 weeks of gestation to delivery
Obstetric outcomes
Time Frame: At time of delivery
Obstetric complications including hypertensive disorders of pregnancy, gestational diabetes, postpartum hemorrhage and cesarean section
At time of delivery
Perinatal outcomes
Time Frame: At time of delivery
Preterm birth, birth weight, congenital malformations, and perinatal mortality (defined as foetal or neonatal death from GA 22+0 to 7 days after birth).
At time of delivery
Hormone levels
Time Frame: Time of insemination and mid-luteal phase (approximately 7-9 days after insemination).
Serum hormone levels measured on the day of insemination, in the mid-luteal phase and on the day of ovulation trigger (optional), including progesterone, estradiol, LH and FSH.
Time of insemination and mid-luteal phase (approximately 7-9 days after insemination).

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.
Kirstine Kirkegaard

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Kirstine Kirkegaard, Clinical Associate Professor, University Clinic for Fertility, Horsens Regional Hospital, Central Denmark Region

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 (Estimated)

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.
April 1, 2026

Primary Completion (Estimated)

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.
June 1, 2029

Study Completion (Estimated)

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.
January 1, 2030

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).
March 27, 2026

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.
March 27, 2026

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.
April 2, 2026

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.
April 2, 2026

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.
March 27, 2026

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.
March 1, 2026

More Information

Terms related to this study

Keywords

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.
  • 05112025
  • 2025-524327-53-00 (Ctis)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be made avaliable.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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