Ying Sheng1, Xuefeng Liu1, Lisa Kane Low2, James A Ashton-Miller3, Janis M Miller4. 1. School of Nursing, University of Michigan, Ann Arbor, MI. 2. School of Nursing, University of Michigan, Ann Arbor, MI; Department of Women's Studies, University of Michigan, Ann Arbor, MI; Department of Obstetrics and Gynecology, School of Medicine, University of Michigan, Ann Arbor, MI. 3. Mechanical and Biomedical Engineering, College of Engineering, University of Michigan, Ann Arbor, MI. 4. School of Nursing, University of Michigan, Ann Arbor, MI; Department of Obstetrics and Gynecology, School of Medicine, University of Michigan, Ann Arbor, MI. Electronic address: janismm@umich.edu.
Abstract
BACKGROUND: Vaginal birth is a risk factor for pubovisceral muscle tear, decreased urethral closure pressure, and urinary incontinence. The relationship between these 3 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. OBJECTIVE: We 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. STUDY DESIGN: We studied 56 women 8 months after their first vaginal birth. All had at least 1 risk factor for pubovisceral muscle tear (eg, forceps and long second 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. A Student 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. RESULTS: The mean age was just a little more than 30 years, with the majority being white. 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 with 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). CONCLUSION: In 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 the ability to recruit the intact pubovisceral muscle to simultaneously contract the urethral striated muscle.
BACKGROUND: Vaginal birth is a risk factor for pubovisceral muscle tear, decreased urethral closure pressure, and urinary incontinence. The relationship between these 3 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. OBJECTIVE: We 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. STUDY DESIGN: We studied 56 women 8 months after their first vaginal birth. All had at least 1 risk factor for pubovisceral muscle tear (eg, forceps and long second 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. A Student 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. RESULTS: The mean age was just a little more than 30 years, with the majority being white. 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 with 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). CONCLUSION: In 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 the ability to recruit the intact pubovisceral muscle to simultaneously contract the urethral striated muscle.
Authors: Maria C P Vila Pouca; João P S Ferreira; Marco P L Parente; Renato M Natal Jorge; James A Ashton-Miller Journal: Am J Obstet Gynecol Date: 2022-01-31 Impact factor: 10.693
Authors: Giovana Vesentini; Angélica M P Barbosa; Débora C Damasceno; Gabriela Marini; Fernanda Piculo; Selma M M Matheus; Raghavendra L S Hallur; Sthefanie K Nunes; Bruna B Catinelli; Claudia G Magalhães; Roberto Costa; Joelcio F Abbade; José E Corrente; Iracema M P Calderon; Marilza V C Rudge Journal: PLoS One Date: 2020-04-03 Impact factor: 3.240