Digital measurement of pelvic muscle strength in childbearing women.

Fourteen primigravidas were evaluated at 32 and 36 weeks antepartum (AP) and 6 weeks postpartum (PP) to test the reliability and validity of a digital measure of pelvic muscle strength using urine control as the criterion. Interrater reliabilities ranged from .67 to .77. Convergent validity was shown by negative correlations between clinical muscle scores and time required to interrupt urine flow at 32 weeks AP (r = -.41), 36 weeks AP (r = -.64) and 6 weeks PP (r = -.71). Validity was also demonstrated in a pattern of lower scores in women who had urine loss during coughing or reported incontinence as compared with those who did not. Women who had cesarean births had higher postpartum pelvic muscle scores with progressively lower scores demonstrated by those who gave birth vaginally without laceration, with episiotomy, and with laceration, F(3, 10) = 5.40, p = .02.