Trust Your Fingers: Determining the Reliability and Validity of the Measurement of the Diastasis of the Rectus Abdominis Muscle by Palpation and Tape Measure

Background: Diastasis of the rectus abdominis muscle (DRAM) occurs in about 60% of pregnant women and often persists after delivery. Currently, the reference standard to measure DRAM is ultrasonography, and physiotherapy is considered first-line treatment. Most physiotherapists do not base their DRAM assessment on ultrasonography but instead on palpatory evaluation with tape measures. This method is neither standardized nor has been tested for its reliability or validity in women with interrectus distance (IRD) of 30 mm and greater. Objectives: To assess the reliability of the measurements of DRAM by palpation with tape measure and to evaluate its validity compared with ultrasonography. Study Design: Prospective observational study. Methods: Two physiotherapists assessed test-retest, intra- and interrater reliability of this method in 20 women with IRD of 30 mm and greater, using intraclass correlations (ICC) and compared the values with ultrasonography to establish its validity using Spearman ρ and Bland-Altman plots. The interval between the 2 sessions was 7 days and greater. Results: The ICC values for test-retest reliability ranged from 0.67 to 0.95 and between 0.40 and 0.85 for intrarater reliability. The ICC values for interrater reliability ranged from 0.13 to 0.29. In terms of validity, correlations were inconsistent with Spearman ρ ranging from −0.24 to 0.74. Conclusion: Single palpatory measurement with tape above the umbilicus and during partial curl-up might detect changes in IRD of 15.5 mm and greater over time in women with IRD of 30 mm and greater. It cannot replace ultrasonographic measurements in accuracy but might be the only available option for IRDs larger than the ultrasonographic probe.