Study of Endometrial Immune and Microbiological Modifications in Cases of Recurrent Implantation Failure and/or Recurrent Pregnancy Loss (IMERR)

February 3, 2026 updated by: Assistance Publique - Hôpitaux de Paris

Study of Immune and Microbiological Modifications of the Endometrium in Cases of Recurrent Implantation Failure and/or Recurrent Pregnancy Loss

The IMERR study aims to improve understanding of certain causes of infertility related to recurrent implantation failure (RIF) and/or recurrent pregnancy loss (RPL), conditions that affect many women undergoing assisted reproductive technology (ART). Despite medical advances, some patients repeatedly fail to achieve pregnancy, or experience repeated miscarriages. These situations may be linked to subtle immune or microbial disturbances in the uterus. This study seeks to identify immune and microbiological profiles in the endometrium during the implantation window-a crucial period when the embryo attaches to the uterine wall. We will compare women who have experienced RIF and/or RPL with women who have had no such history. Blood and uterine samples will be analyzed to investigate whether certain immune or microbial features are associated with these reproductive failures. The ultimate goal is to uncover predictive factors that may explain why some women experience implantation failure or pregnancy loss, and to lay the foundation for future personalized treatments to improve reproductive outcomes.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The IMERR study is a prospective, monocentric, controlled interventional study aiming to identify immune and microbiological signatures in the eutopic endometrium of women undergoing ART (IVF/ICSI), with and without a history of recurrent implantation failure (RIF) and/or recurrent pregnancy loss (RPL). RIF is defined as the absence of clinical pregnancy after at least three embryo transfers of good-quality blastocysts, and RPL as two or more consecutive pregnancy losses before 24 weeks of gestation.

Participants will be divided into two groups: a study group (with RIF and/or RPL) and a control group (without RIF or RPL). Endometrial biopsies will be collected during the implantation window, alongside peripheral blood and vaginal samples. These samples will undergo immunological and microbiological analyses, including histology, immunophenotyping, and microbiota profiling.

The study aims to (i) Characterize immune cell populations in the endometrium and blood, (ii) Investigate the endometrial microbiome and its potential dysbiosis, (iii) Explore associations between these biological profiles and clinical features such as endometriosis, adenomyosis, chronic endometritis, or uterine contractility disorders.

The study includes 100 participants and spans a total duration of 60 months (36 months for inclusion and 24 months of follow-up). A subgroup analysis will assess the association between immuno-microbiological profiles and clinical outcomes after embryo transfer within the 24-month post-inclusion period.

By identifying predictive markers of RIF and RPL, this study may help establish new diagnostic tools and personalized treatment strategies in reproductive medicine.

Study Type

Interventional

Enrollment (Estimated)

100

Phase

  • 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 Backup

Study Locations

  • France
    • IDF
      • Paris, IDF, France, 75014
        • Service de Gynécologie Obstétrique II et Médecine de la Reproduction - Cochin Hospital
        • Contact:
        • Contact:

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

Ages Eligible for Study

  • Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Female aged ≥18 and <36 years
  • Undergoing assisted reproductive technology (ART) in a fertility center
  • Covered by the French national health insurance system

  • Belonging to one of two groups:

    • Study group: history of recurrent implantation failure (RIF) and/or recurrent pregnancy loss (RPL)
    • Control group: no history of RIF or RPL

Exclusion Criteria:

  • Pregnant at inclusion
  • Refusal to provide written informed consent
  • Antibiotic use within one month prior to endometrial biopsy Positive serology for hepatitis B, hepatitis C or HIV
  • Uterine anatomical abnormalities (e.g., polyps, cavity-distorting fibroids, untreated hydrosalpinx)
  • Known chromosomal abnormality in either partner
  • Known autoimmune disease, thrombophilia, or antiphospholipid antibody syndrome
  • Persons under legal protection (e.g., guardianship, curatorship)

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: Basic Science
  • Allocation: Non-Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Other: RIF/RPL group
Women undergoing ART with a history of recurrent implantation failure (RIF) and/or recurrent pregnancy loss (RPL).
Diagnostic test: Endometrial Biopsy
Endometrial biopsy with Cornier Pipelle (part of the treatment in the RIF/RPL group and some patients of the control group / added for the research for the other patients of the control group)
Diagnostic test: Vaginal Swab
Vaginal sample collection using a cotton swab. Part of the treatment
Diagnostic test: Blood sample
Peripheral blood draw. Part of the treatment + 10 mL additional for research
Diagnostic test: Pelvic ultrasound (±pelvic MRI)
Pelvic ultrasound (±pelvic MRI). Part of the treatment
Other: Control group
Women undergoing ART without a history of RIF or RPL.
Diagnostic test: Endometrial Biopsy
Endometrial biopsy with Cornier Pipelle (part of the treatment in the RIF/RPL group and some patients of the control group / added for the research for the other patients of the control group)
Diagnostic test: Vaginal Swab
Vaginal sample collection using a cotton swab. Part of the treatment
Diagnostic test: Blood sample
Peripheral blood draw. Part of the treatment + 10 mL additional for research
Diagnostic test: Pelvic ultrasound (±pelvic MRI)
Pelvic ultrasound (±pelvic MRI). Part of the treatment

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Profiling of endometrial immune cell populations
Time Frame: Baseline

Profiling of endometrial immune cell populations (proportion of subpopulation) during the implantation window using single-cell transcriptomics and/or flow cytometry.

Endometrial biopsies will be collected during the implantation window. Immune cell populations will be characterized using either single-cell RNA sequencing (scRNA-seq) and /or multiparametric flow cytometry, depending on technical feasibility and sample quality. For scRNA-seq, transcriptomic analysis will be performed (e.g., using the 10x Genomics platform), and immune cell types will be identified via clustering and annotation algorithms. For flow cytometry, immune subsets will be identified and quantified based on surface marker expression. Comparisons of immune profiles will be made between women with and without a history of RIF and/or RPL.
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Microbiological profiling of endometrial tissue
Time Frame: Baseline

Microbiological profiling of endometrial tissue during the implantation window using next-generation sequencing (NGS)

Endometrial microbiota will be characterized by next-generation sequencing (NGS) of DNA extracted from endometrial biopsy samples collected during the implantation window. Diversity metrics (alpha and beta diversity) and relative abundances of microbial taxa will be compared between women with and without a history of RIF and/or RPL.
Baseline
Characterization of peripheral blood immune cell populations
Time Frame: Baseline

Characterization of peripheral blood immune cell populations during the implantation window using single-cell transcriptomics and/or flow cytometry

Peripheral blood samples will be collected at inclusion. Immune profiling will be performed to characterize circulating immune cell subpopulations. Depending on feasibility and sample quality, either single-cell RNA sequencing (scRNA-seq) and / or multiparametric flow cytometry may be used. Immune profiles will be compared between women with and without a history of RIF and/or RPL.
Baseline
Exploratory analysis of associations between immune and microbiological profiles and clinical, radiological, and histological characteristics
Time Frame: Baseline
This outcome consists of exploratory analyses assessing the associations between previously measured immune and microbiological profiles (from endometrial tissue) and (i) clinical outcomes (e.g., pregnancy, miscarriage, live birth), (ii) radiological findings (e.g., adenomyosis, uterine contractility), and (iii) histological/bacteriological findings (e.g., chronic endometritis with CD138+ cells or vaginal cultures). No new biological measurements will be performed. Each association will be reported as a separate statistical outcome (e.g., odds ratios, p-values)
Baseline
Exploratory analysis of associations between immune and microbiological profiles and clinical, radiological, and histological characteristics
Time Frame: Through 24 months of follow-up
This outcome consists of exploratory analyses assessing the associations between previously measured immune and microbiological profiles (from endometrial tissue) and (i) clinical outcomes (e.g., pregnancy, miscarriage, live birth), (ii) radiological findings (e.g., adenomyosis, uterine contractility), and (iii) histological/bacteriological findings (e.g., chronic endometritis with CD138+ cells or vaginal cultures). No new biological measurements will be performed. Each association will be reported as a separate statistical outcome (e.g., odds ratios, p-values)
Through 24 months of follow-up

Collaborators and Investigators

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

Sponsor

Assistance Publique - Hôpitaux de Paris

Collaborators

Institut National de la Santé Et de la Recherche Médicale, France
URC-CIC Paris Descartes Necker Cochin
ADREGOF

Investigators

  • Principal Investigator: Mathilde Bourdon, MD, PhD, Service de Gynécologie Obstétrique II et Médecine de la Reproduction - Cochin Hospital

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 (Estimated)

April 1, 2026

Primary Completion (Estimated)

April 1, 2029

Study Completion (Estimated)

April 1, 2031

Study Registration Dates

First Submitted

May 26, 2025

First Submitted That Met QC Criteria

November 24, 2025

First Posted (Actual)

December 4, 2025

Study Record Updates

Last Update Posted (Actual)

February 5, 2026

Last Update Submitted That Met QC Criteria

February 3, 2026

Last Verified

February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • APHP241344
  • 2024-A02100-47 (Other Identifier: France : Ministry of Health)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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