Role of Pelvic Muscle Strength Change in Explaining Incontinence Reduction by Pelvic Muscle Training for Stress Urinary Incontinence

Background: First-line stress urinary incontinence (SUI) treatment in postpartum is pelvic floor muscle training (PFMT), typically involving minimally 30 contractions (Exercise method) along with instruction in contracting with intraabdominal pressure rise, such as cough or sneeze (Knack method). PFMT effect on leakage is thought to be due to exercise-related pelvic muscle strength gain. Reports of statistical correlation of relationship between strength change and incontinence change is lacking. Long-term adherence to Exercise method is challenging. Knack method has shown immediate effect in clinic environment on standing stress test without time for strength change. The long-term goal of our work is to find the most parsimonious but effective form of PFMT for busy postpartum women with SUI. To begin, we aim to:

Aim:  Determine if pelvic muscle strength change correlates with SUI symptoms change in postpartum women assigned both Exercise method and Knack method.

Methods: Design: cohort longitudinal study with women evaluated at 6 weeks and 7 months postpartum for levator ani strength and for urinary incontinence (Sandvik score, Antonakos score).  151 postpartum women, all taught each pelvic muscle training method (Exercise and Knack) with hands on instruction during a pelvic exam and visual feedback of contraction by ultrasound. Data were analyzed by Spearman’s correlation for strength of association between strength change and incontinence reduction for women who had complete data at both time points.

Results: Correlations coefficients were weak and non-significant between the change of pelvic muscle strength and the change in incontinence measures: Sandvik (r=-.061, p=.66, n=56), Antonakos (r=.140, p=.25, n=69) questionnaires.

Conclusion: In postpartum women, pelvic muscle strength change does not explain change in incontinence over the postpartum year. Further research is advised to explore the role of skill acquisition through the Knack method, the role of natural history of recovery, and other potential explanation for improvement of SUI.