Pregnancy and childbirth often result in muscular alterations. Stress urinary incontinence and pelvic organ prolapse as well as a diastasis recti abdominis can result in decreased quality of life. Women often require an assessment of their pelvic floor muscle function and diastasis recti abdominis after pregnancy. However, there is no gold standard in assessing these muscles postpartum. The aim of this study was to test the reliability of clinically applicable assessment methods for the pelvic floor muscles postpartum according to the standardized terminology of the International Continence Society. Another aim was to test the reliability of clinically applicable assessment methods for the width, depth and bulging of the diastasis recti abdominis postpartum.

Between September 2018 and February 2020, two hundred and twenty-two women, who gave birth max 12 weeks ago, were recruited from Swedish antenatal and childbirth centres and via social media. All women underwent an assessment of the pelvic floor muscles and diastasis recti abdominis 12 weeks after delivery. The pelvic floor muscle assessment contained vaginal palpation and observation of voluntary and involuntary contraction as well as vaginal palpation of voluntary relaxation. The width of the diastasis recti abdominis were measured with a caliper. The depth and bulging of the diastasis recti abdominis were assessed by observation and palpation. The assessments were performed at three rehabilitation centres in Sweden, 90 women were assessed at rehabilitation centre 1, 103 at rehabilitation centre 1 and 29 at rehabilitation centre 3. At each centre two independent physiotherapists assessed the women in random order. For statistical test of reliability, kappa values were used for dichotomous variables, weighted kappa for variables from ordinal scales and ICC-values for continuous variables.

Mean age of the women was 33 years (SD 3.3); 87% gave birth vaginally and 13% via caesarean section; 137 were primiparous (62%) and 85 were multiparous (38%). Moderate to substantial reliability were found for the assessment of maximum voluntary contraction of the pelvic floor muscles by vaginal palpation at all three rehabilitation centres. The assessment of voluntary contraction by observation showed moderate reliability. There were inconsistent findings between the three centres regarding the assessment of involuntary contraction by vaginal palpation and observation and voluntary relaxation, with slight to moderate kappa and weighted kappa values. The assessment of the width of the diastasis recti abdominis by caliper showed moderate to good reliability after three months of training in using this assessment method. The assessment of the depth and bulging of the diastasis recti abdominis showed fair kappa values.

In the assessment of the pelvic floor muscles of postpartum women is vaginal palpation of maximum voluntary contraction a reliable method. The assessment of voluntary contraction by observation has lower reliability. No reliable assessment method for the assessment of involuntary contraction and voluntary relaxation were found. Due to the inconsistent findings between the three rehabilitation centres for these assessments a further analysis of possible assessment bias must be done. The width of the diastasis recti abdominis can be assessed with a caliper in postpartum women. No reliable method for the assessment of the depth and bulging were found in this study.

More and more women are demanding an assessment of their pelvic floor muscles and diastasis recti abdominis after pregnancy. This study shows that vaginal palpation of maximum voluntary contraction of the pelvic floor muscles could be used as a reliable assessment method postpartum. More research about the results of this assessment and their consequences on exercise advices to postpartum women and the treatment of symptoms like stress urinary incontinence and pelvic organ prolapse postpartum must be done. 

A caliper can be used in the assessment of the width of diastasis recti abdominis although it requires some experience and training before use. It must be studied which exercise advice should be given based on the result of this assessment. Furthermore, is must be investigated where the cut- off point for pain and dysfunction and the severity of the diastasis recti abdominis is. 

More research is needed to find reliable assessment method for other pelvic floor muscle functions than voluntary contraction and for the depth and bulging of the diastasis recti abdominis.