Diaphragm and Breathing Muscle Characteristics in Women With and Without Diastasis Recti Abdominis After Childbirth (DRA-DIAPH)

April 9, 2026 updated by: Anastasia Skoura, University of Patras

Diaphragm Characteristics and Respiratory Muscle Function in Parous Women With and Without Diastasis Recti Abdominis

Diastasis Recti Abdominis (DRA) is a common condition experienced postpartum, in which the abdominal muscles separate along the midline of the abdomen due to stretching and thinning of the linea alba. It's a common condition, affecting 66-100% of women post-birth and may be associated with changes in abdominal support, posture, breathing, and trunk function. Although DRA primarily affects the muscles of the abdominal wall, it is speculated that other muscles controlling and stabilizing the trunk, such as the pelvic floor muscles or the diaphragm, might be affected as well. Currently, several studies have investigated the possible negative effects of DRA on pelvic floor function. However, little is known about how it may be related to diaphragm function and accessory breathing muscles.

The purpose of this observational study is to compare diaphragm characteristics and function, and accessory breathing muscle strength in women who have given birth, with and without DRA.

To make this possible, adult parous women from the broader Achaia region are assessed and allocated into two predefined groups based on the presence or absence of DRA. Participants undergo a single assessment session including rehabilitative ultrasound imaging (RUSI) of the diaphragm and standardized tests of inspiratory muscle strength. Additional demographic and clinical information related to pregnancy and physical activity is also recorded. The main hypothesis of this study is that women with DRA demonstrate altered diaphragm function, as well as reduced inspiratory muscle strength, compared to women without DRA. The study aims to improve understanding of the possible relationship between DRA and breathing function after childbirth and to support future research and rehabilitation approaches for women with the condition.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Diastasis recti abdominis (DRA) is a common postpartum condition, characterized by stretching and thinning of the linea alba and separation of the two rectus abdominis muscles along the midline of the abdomen. Beyond cosmetic concerns, DRA has been associated with impaired abdominal wall function, altered trunk stability, and potential changes in respiratory mechanics due to the close anatomical and functional relationship between the abdominal muscles and the diaphragm.

The diaphragm plays a central role in respiration and trunk stabilization, working synergistically with the abdominal wall to regulate intra-abdominal pressure (IAP) and postural control. Alterations in abdominal wall integrity, such as those observed in DRA, may therefore influence diaphragm function and mobility, as well as overall respiratory muscle performance. However, evidence regarding the relationship between DRA and diaphragm function currently remains limited.

This observational, cross-sectional study aims to examine diaphragm characteristics and inspiratory muscle strength in parous women with and without DRA. Participants are allocated into two predefined groups according to the presence or absence of DRA, based on a standardized imaging assessment.

Diaphragm function is assessed using rehabilitative ultrasound imaging (RUSI) techniques, performed by a trained physiotherapist, following standardized procedures. Ultrasound images are obtained during specific breathing maneuvers to determine diaphragm thickness and excursion. Inspiratory muscle strength is assessed using a standardized procedure to test maximal inspiratory pressure (MIP), S-Index and Peak Inspiratory Pressure (PIF) using a POWERbreathe KH2 device. All measurements are conducted during a single assessment session, and are led by three experienced physiotherapists. Furthermore, demographic data and relevant obstetric and clinical characteristics, such as age, body mass index (BMI), parity, and time since last delivery, are recorded to describe the study population.

The study aims to explore whether women with DRA demonstrate differences in diaphragm-related parameters and inspiratory muscle strength compared with women without DRA. By improving understanding of the interaction between the abdominal wall and respiratory muscles after childbirth, this research may contribute to the development of more targeted assessment strategies and rehabilitation approaches in postpartum care.

Study Type

Observational

Enrollment (Estimated)

42

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

  • Greece
    • Achaia
      • Pátrai, Achaia, Greece, 26504
        • Recruiting
        • Laboratory of Clinical Rehabilitation and Research (CPRlab), University of Patras
        • Contact:
        • Sub-Investigator:
          • Katerina Afroditi Chalki, BSc

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

Yes

Sampling Method

Non-Probability Sample

Study Population

Parous adult women from the local community (broader Achaia region) recruited through invitations and referrals and assessed in a clinical research setting.

Description

Inclusion Criteria:

  • Female sex
  • Aged 18 to 50 years
  • Parous women (at least one previous childbirth)
  • At least 6 months postpartum at the time of assessment (and within 5 years postpartum)
  • Ability to understand and communicate in Greek
  • Willingness to participate and provide informed consent

Exclusion Criteria:

  • Current pregnancy
  • Delivery within the previous 6 months
  • History of severe chronic respiratory disease (e.g., chronic obstructive pulmonary disease, chronic bronchitis, pulmonary emphysema, pulmonary fibrosis)
  • Presence of connective tissue disorders
  • Presence of neurological disorders
  • Severe musculoskeletal conditions that could affect trunk or respiratory function or limit participation in testing procedures (severe low back pain, sciatica etc.)
  • Previous abdominal surgery, with the exception of cesarean section

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

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Women with diastasis recti abdominis
Parous women diagnosed with diastasis recti abdominis using a standardised ultrasonographic assessment to measure the inter-recti distance (IRD).
Diagnostic test: Ultrasonographic assessment of the diaphragm
Rehabilitative ultrasound imaging (RUSI) to assess diaphragm thickness and excursion under specific respiratory maneuvers.
Diagnostic test: Inspiratory muscle testing
A standardized inspiratory muscle strength testing procedure using a POWERbreathe KH2 device to assess maximal inspiratory pressure (MIP), S-Index and peak inspiratory flow (PIF).
Women without diastasis recti abdominis
Parous women without diastasis recti abdominis, as confirmed by standardized ultrasonographic assessment of inter-recti distance (IRD).
Diagnostic test: Ultrasonographic assessment of the diaphragm
Rehabilitative ultrasound imaging (RUSI) to assess diaphragm thickness and excursion under specific respiratory maneuvers.
Diagnostic test: Inspiratory muscle testing
A standardized inspiratory muscle strength testing procedure using a POWERbreathe KH2 device to assess maximal inspiratory pressure (MIP), S-Index and peak inspiratory flow (PIF).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Inspiratory diaphragm thickness
Time Frame: Baseline
Diaphragm thickness measured via ultrasound in cm at the end of a full inspiration at a standardized anatomical location.
Baseline
Expiratory diaphragm thickness
Time Frame: Baseline
Diaphragm thickness measured via ultrasound in cm at the end of a full expiration at a standardized anatomical location.
Baseline
Diaphragm excursion
Time Frame: Baseline
Diaphragm excursion measured via ultrasound in cm during quiet respiration at 60% of inspiratory capacity (IC).
Baseline

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Maximal Inspiratory Pressure (MIP)
Time Frame: Baseline
Maximal Inspiratory Pressure (MIP) measured during a forceful inspiratory effort in cmΗ2Ο, using the POWERbreathe KH2 device.
Baseline
S-Index
Time Frame: Baseline
S-Index, a strength estimate measured in cmH2O during a forceful inspiration performed using the POWERbreathe KH2 device.
Baseline
Peak Inspiratory Flow (PIF)
Time Frame: Baseline
Peak Inspiratory Flow (PIF) measured in L/sec, during the same forceful inspiratory maneuver as SIndex, using the POWERbreathe KH2 device.
Baseline

Collaborators and Investigators

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

Sponsor

University of Patras

Investigators

  • Principal Investigator: Evdokia Billis, PhD, University of Patras

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)

May 19, 2025

Primary Completion (Actual)

April 3, 2026

Study Completion (Estimated)

May 13, 2026

Study Registration Dates

First Submitted

January 28, 2026

First Submitted That Met QC Criteria

January 28, 2026

First Posted (Actual)

February 5, 2026

Study Record Updates

Last Update Posted (Actual)

April 13, 2026

Last Update Submitted That Met QC Criteria

April 9, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Other Study ID Numbers

  • DRA-DIAPHRAGM-PILOT

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

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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