Changes in pelvic muscle strength and stress urinary incontinence associated with childbirth.

Pelvic muscle strength and stress urinary incontinence were studied in 20 nulliparous women at 32 to 36 antepartum weeks and 6 postpartum weeks. Measures used included a digital muscle strength score, observed incontinence, and urine flow interruption. Pelvic muscle strength declined from the antepartum to postpartum periods in women with vaginal births; however, women with greater antepartal pelvic muscle strength tended to preserve a higher level of strength during the postpartum period. In general, less pelvic muscle strength was found in women who demonstrated stress urinary incontinence.