Association of Pubovisceral Muscle Tear with Functional Capacity of Urethral Closure: Evaluating Maternal Recovery from Labor and Delivery: Pubovisceral Muscle Tear and Urethral Closure Pressure.

Abstract

BACKGROUND\nVaginal birth is a risk factor for pubovisceral muscle tear, decreased urethral closure pressure, and urinary incontinence. The relationship between these three factors is complicated. Urinary continence relies on maintaining urethral closure pressure; particularly when low urethral closure pressure can usefully be augmented by a volitional pelvic muscle (Kegel) contraction just before and during stress events like a cough. However, it is unknown whether a torn pubovisceral muscle decreases the ability to increase urethral closure during an attempted pelvic muscle contraction.\n\n\nOBJECTIVE\nWe tested the null hypothesis that a pubovisceral muscle tear does not affect the ability to increase urethral closure pressure during a volitional pelvic muscle contraction in the Evaluating Maternal Recovery from Labor and Delivery (EMRLD) study.\n\n\nSTUDY DESIGN\nWe studied 56 women 8 months after their first vaginal birth. All had at least one risk factor for pubovisceral muscle tear (e.g., forceps and long 2nd stage). A tear was assessed bilaterally by magnetic resonance imaging. Urethral closure pressure was measured both at rest and during an attempted volitional pelvic muscle contraction. Student s t test was used to compare urethral closure pressures. Multiple linear regression was used to estimate the effect of a magnetic resonance imaging-confirmed pubovisceral muscle tear on volitionally contracted urethral closure pressure after adjusting for resting urethral closure pressure.\n\n\nRESULTS\nThe mean age was just over 30 years with the majority being Caucasian. By magnetic resonance imaging measure, unadjusted for other factors, the 21 women with tear had significantly lower urethral closure pressure during an attempted contraction compared to the 35 women without tear (65.9 vs 86.8 cm H2O respectively, P=.004), leading us to reject the null hypothesis. No significant group difference was found in resting urethral closure pressure. After adjusting for resting urethral closure pressure, pubovisceral muscle tear was associated with lower urethral closure pressure (beta = - 21.1, P=.001).\n\n\nCONCLUSIONS\nIn the first postpartum year the presence of a pubovisceral muscle tear did not influence resting urethral closure. However, women with a pubovisceral muscle tear achieved a 25% lower urethral closure pressure during an attempted pelvic muscle contraction than those without a pubovisceral muscle tear. These women with pubovisceral muscle tear may not respond to classic behavioral interventions, such as squeeze when you sneeze or strengthen through repetitive pelvic muscle exercises. When a rapid rise to maximum urethral pressure is used as a conscious volitional maneuver, it appears to be reliant on ability to recruit the intact pubovisceral muscle in order to simultaneously contract the urethral striated muscle.