Clinical assessment of pelvic floor and abdominal muscles 3 months post partum: an inter-rater reliability study

OBJECTIVES: Evaluation of the inter-rater reliability of clinical assessment methods for pelvic floor muscles and diastasis recti abdominis post partum. DESIGN: A multicentre inter-rater reliability study. SETTING: Three primary care rehabilitation centres in Sweden. PARTICIPANTS: A total of 222 participants were recruited via advertising at Swedish maternity care units and social media. Eligibility for participation included female gender, ≥18 years, at maximum 3 months after childbirth. Exclusion criteria were chronic pelvic girdle pain and/or low back pain and/or pelvic floor tear grade III/IV. At each centre, 2 physiotherapists, with training and experience in pelvic floor assessment, assessed the 222 women according to a standardised protocol in random order. OUTCOME MEASURES: Inter-rater reliability of the assessment of pelvic floor muscle function (involuntary and voluntary contraction and voluntary relaxation) and diastasis recti abdominis (width, depth and bulging). RESULTS: Vaginal palpation of maximal voluntary contraction revealed a kappa value of 0.69 (95% CI 0.62 to 0.76). Assessments of involuntary contraction and voluntary relaxation yielded inconsistent results, with slight-to-moderate weighted kappa values ranging from 0.10 to 0.51. After 2 months of training in applying this method, diastasis recti abdominis width measured at the umbilicus by calliper yielded an intraclass correlation coefficient value of 0.83 (95% CI 0.76 to 0.87). Assessments of diastasis recti abdominis depth and bulging showed moderate kappa values, with reservation for some inconsistency between the centres. CONCLUSIONS: Vaginal palpation of pelvic floor muscle strength is a reliable method for the postpartum muscle assessment. Additional research is needed to identify reliable assessment method for other pelvic floor muscle functions like involuntary contraction and voluntary relaxation. With some training, a calliper is a reliable instrument for measuring the postpartum diastasis recti abdominis width. This study provides novel thoughts about how to measure diastasis recti abdominis depth and bulging. TRIAL REGISTRATION NUMBER: NCT03703804.