Impact of Operation on Fertility for Women With Severe Endometriosis (EFFORT)

March 7, 2026 updated by: Ulla Breth Knudsen, Horsens Hospital

Comparing Impact of Operation and Fertility Treatment on Fertility for Women With Deep Infiltrating Endometriosis: A Multicenter Randomized Controlled Trial

The EFFORT study compares the impact on fertility of operation or fertility treatment (IVF, in vitro fertilization) in a multicenter randomized controlled trial. The study population consists of women with colorectal deep infiltrating endometriosis and a pregnancy intention. These women will be randomized to either of the two treatment groups: Group A = Operation or Group B = fertility treatment (IVF). Group A will be further divided postoperatively into spontaneous conception or IVF depending on the Endometriosis Fertility Index score.

Study Overview

Status

Status

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

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 (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.
38

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.
  • Not Applicable

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.
  • Name: Ulla B Knudsen, Professor
  • Phone Number: +45 78426592
  • Email: ubk@dadlnet.dk

Study Contact Backup

Study Locations

  • Denmark
    • Central Region
      • Aarhus N, Central Region, Denmark, 8200
        • Aarhus University Hospital
      • Horsens, Central Region, Denmark, 8700
        • Horsens Regional Hospital
  • France
      • Bordeaux, France
        • The Endometriosis Center, Clinique Tivoli-Ducos

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 38 years (Adult)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Rectosigmoid endometriosis and wish for surgery
  • Pregnancy intention for at least 6 months
  • AMH above 5 pmol/ml
  • Maximum of 2 previous IVF treatments
  • Male partner

Exclusion Criteria:

  • Endometriosis involving the ureter unilaterally or bilaterally (randomization unethical)
  • BMI above 32
  • Contraindication for IVF (untreated uterine factor infertility, untreated/maltreated systemic or malignant disease, oocyte aspiration severely riskful (e.g. severe abdominal adhesions)
  • No wish for randomization

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.
Active Comparator: Operation
Operation for severe endometriosis
Procedure: Operation
Operation for deep infiltrating endometriosis
Active Comparator: Fertility treatment
Fertility treatment for women with severe endometriosis.
Procedure: Fertility treatment
In vitro fertilisation (IVF) and IVF-intracytoplasmic injection (ICSI)

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
Cumulative pregnancy rate (CPR)
Time Frame: 18 months
Rate of cumulative pregnancies defined as a fetal heartbeat by ultrasound at gestational week 6 to 8
18 months
Live birth rate (LBR)
Time Frame: 18 months
Rate of live births
18 months

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
Non-viable pregnancies
Time Frame: 18 months
Number of biochemical pregnancies, miscarriages, missed abortions, extrauterine pregnancies and pregnancies of unknown location (PUL)
18 months
Ovarian potential
Time Frame: Baseline and 9-18 months
Concentration of Anti-Müllerian hormone (AMH)
Baseline and 9-18 months
Time to pregnancy
Time Frame: 18 months
Shortest time from intervention date to date of visualisation of the first ongoing pregnancy
18 months
Postoperative complications
Time Frame: 18 months
Rate of complications in accordance to Clavien-Dindo Classification, including anastomotic leakage or stenosis, ureteral lesion or obstruction, pelvic abscess, fistula, bladder or bowel perforation and urinary retention
18 months
Fertility treatment complications
Time Frame: 18 months
Rate of hospital admissions, bleeding, superinfection, worsening of pain or having ovarian hyperstimulation syndrome (OHSS)
18 months
Pain score
Time Frame: Baseline, 9 and 18 months
Numeric Rating Scale (NRS) score from 0 to 10, where 10 implies the worst pain
Baseline, 9 and 18 months
Quality of Life (QoL)
Time Frame: Baseline, 9 and 18 months
Development in Endometriosis Health Profile (EHP-30+23), including section C (sexual function QoL questions) and section F (fertility QoL questions)
Baseline, 9 and 18 months
Delayed bowel function
Time Frame: Baseline, 9 and 18 months
Development in bowel function rated by Low Anterior Resection Syndrome (LARS) score
Baseline, 9 and 18 months
Delayed bladder function
Time Frame: Baseline, 9 and 18 months
Development in urinary tract function rated by International Consultation on Incontinence Questionnaire (ICIQ- FLUTS)
Baseline, 9 and 18 months
Endometriosis hormonal and inflammatory status
Time Frame: Baseline and 9-18 months
Concentrations of hormonal and inflammatory markers in blood samples
Baseline and 9-18 months
Follicles, oocytes, fertilized oocytes, blastocysts, and frozen embryos
Time Frame: 18 months
Number of follicles as measured at last scan prior to oocyte pick-up (OPU), number of oocytes at OPU, fertilized oocytes, blastocysts and frozen embryos
18 months
Blastocyst morphology score
Time Frame: 18 months
Gardner scoring system, Steer grading system, Veecks criteria, or other scoring systems of blastocyst morphology
18 months

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.
Horsens Hospital

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.
Aarhus University Hospital
Clinique Tivoli Ducos

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

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.
November 25, 2020

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.
March 1, 2026

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.
March 1, 2026

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).
October 22, 2020

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.
October 29, 2020

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.
October 30, 2020

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 10, 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 7, 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, 2025

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.
  • Horsens MR

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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