Meeting paperAUGS paperBiomechanical properties of the vaginal wall: effect of pregnancy, elastic fiber deficiency, and pelvic organ prolapse
Section snippets
Mice
A total of 25 female mice were studied and killed in accordance with the standards of humane animal care described by the National Institutes of Health Guide for the Care and Use of Laboratory Animals, using protocols that have been approved by the Institutional Animal Care and Use Committee of University of Texas Southwestern Medical Center. Animals were housed under a 12-hour light cycle at 22°C. All wild-type (WT) mice used in these studies were C3BL/6J. Fbln5−/− mice were of a similar mixed
Results
The stress-strain curves of vaginal tissues from late-pregnant animals and nonpregnant controls are shown in Figure 1. In vaginal tissues from nonpregnant WT mice, small increases in strain resulted in marked increases in stress generation that indicated a stiff, nondistensible tissue. In contrast, in vaginal tissues from pregnant animals, large increases in strain resulted in relatively small increases in stress, and stress continued to increase until tissue diameters reached twice that of
Changes with pregnancy
In this study with full-thickness sections of isolated mouse vagina, we found that pregnancy confers remarkable physiologic changes in biomechanical properties. During pregnancy, the resting diameter of the vaginal wall is increased and may distend up to 3 times in diameter, compared with vaginal tissues from nonpregnant animals (ie, 2-fold increase in strain). Tissue stiffness is decreased (ie, distensibility is increased). These appear to be intuitive compensations to allow for parturition.
Acknowledgment
We thank Mr Jesús Acevedo for expert technical assistance.
References (17)
- et al.
Childbirth and pelvic floor dysfunction: an epidemiologic approach to the assessment of prevention opportunities at delivery
Am J Obstet Gynecol
(2006) - et al.
Urethral collagen morphologic characteristics among women with genuine stress incontinence
Am J Obstet Gynecol
(2000) - et al.
Pelvic organ prolapse in fibulin-5 knockout mice: pregnancy changes in elastic fiber homeostasis in mouse vagina
Am J Pathol
(2007) - et al.
Morphometric analysis of smooth muscle in the anterior vaginal wall of women with pelvic organ prolapse
Am J Obstet Gynecol
(2002) - et al.
Morphometric properties of the posterior vaginal wall in women with pelvic organ prolapse
Am J Obstet Gynecol
(2002) - et al.
Collagen content of nonsupport tissue in pelvic organ prolapse and stress urinary incontinence
Am J Obstet Gynecol
(2003) - et al.
A biomechanical study of the strength of vaginal tissues: results on 16 post-menopausal patients presenting with genital prolapse
Eur J Obstet Gynecol Reprod Biol
(2004) - et al.
Epidemiology of surgically managed pelvic organ prolapse and urinary incontinence
Obstet Gynecol
(1997)
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This study was supported by National Institutes of Health grant AG028048.
Cite this article as: Rahn DD, Ruff MD, Brown SA, Tibbals HF, Word RA. Biomechanical properties of the vaginal wall: effect of pregnancy, elastic fiber deficiency, and pelvic organ prolapse. Am J Obstet Gynecol 2008;198:590.e1-590.e6.
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