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Comparative Study
. 2008 May;198(5):590.e1-6.
doi: 10.1016/j.ajog.2008.02.022.

Biomechanical properties of the vaginal wall: effect of pregnancy, elastic fiber deficiency, and pelvic organ prolapse

David D Rahn  1 , Matthew D Ruff, Spencer A Brown, Harry F Tibbals, R Ann Word
Affiliations
Comparative Study

Biomechanical properties of the vaginal wall: effect of pregnancy, elastic fiber deficiency, and pelvic organ prolapse

David D Rahn et al. Am J Obstet Gynecol. 2008 May.

Abstract

Objective: The purpose of this study was to identify pregnancy-induced changes in biomechanical properties of the vaginal wall and to compare these with fibulin-5 knockout mice (Fbln5(-/-)) with and without prolapse.

Study design: Mid-vaginal segments of nonpregnant and late-pregnant wild-type mice, Fbln5(-/-) with prolapse mice and Fbln5(-/-) mice without prolapse were studied. Tissue length at failure, maximal strain, maximal stress, and tissue stiffness were determined.

Results: Compared with nonpregnant mice, vaginas of pregnant and Fbln5(-/-) (with prolapse) mice exhibited decreased maximal stress, increased distensibility and strain, and decreased stiffness. Tissues from Fbln5(-/-) mice without prolapse were similar to nonpregnant wild-type animals.

Conclusion: Pregnancy confers remarkable changes in the vaginal wall that include increased distensibility and decreased stiffness and maximal stress. Elastinopathy alone is insufficient to cause significant changes in these properties, but prolapse confers additional alterations in distensibility and stiffness that are similar to those changes that have been observed in pregnancy. These changes may contribute to the poor durability of many restorative surgical procedures for prolapse.

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Figures

Figure 1
Figure 1. Stress-strain relationships of vaginal tissues from pregnant day-18 wild type mice (open circle, n = 6) compared with nonpregnant wild type controls (closed circle, n = 8)
Strain was calculated as the change in length of the specimen divided by its slack length, and stress is expressed in Newtons per cross-sectional area. Mean values are shown with standard errors.
Figure 2
Figure 2. Stress-strain relationships of vaginal tissues from Fbln5-/- mice with prolapse (open circles, n = 7) and Fbln5-/- mice without prolapse (closed circles, n = 4) compared with nonpregnant wild type controls (closed triangles, n = 6)
Mean values are shown with standard errors.
See this image and copyright information in PMC

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