Urethral collagen morphologic characteristics among women with genuine stress incontinence

Objective: This was a study of the morphologic characteristics of urethral collagen in women with stress incontinence and continent control women. Study Design: Urethral needle biopsy specimens were obtained from 31 women. Fifteen women were continent, and the other 16 had undergone full urogynecologic assessment for symptoms of urinary incontinence. Biopsy specimens were assessed under electron microscopy. Mean collagen fibril diameter was measured and collagen morphologic characteristics were assessed. Results: The biopsy specimens from 30 women were included in the analysis. Collagen fibril diameter did not vary with continence status, the presence of pelvic organ prolapse, age, race or hormonal status. Alterations in collagen fibril morphologic characteristics were evident in the biopsy specimens from nine patients with incontinence. The alterations in collagen morphologic characteristics fell into three patterns, which for convenience were referred to as the obscured pattern, the dense pattern, and the degenerative pattern. Conclusion: Altered collagen morphologic characteristics are found in some patients with stress incontinence, and possible causes for those alterations are suggested by their appearances. (Am J Obstet Gynecol 2000;182:1565-74.)