Analysis of collagen status in premenopausal nulliparous women with genuine stress incontinence

Objective To determine if differences exist in the collagen status of premenopausal nulliparous women with genuine stress incontinence compared with continent controls. Design Thirty-six premenopausal nulliparous women with urodynamically-proven genuine stress incontinence were compared with 25 controls. All the women studied had a periurethral vaginal biopsy taken of approximately 30-50 mg in wet weight. This biopsy was then analysed to determine the collagen content, the type I:III collagen ratio and the collagen cross-link content. Setting A tertiary referral urodynamic unit. Results The nulliparous women with genuine stress incontinence had significantly less collagen in their tissues (P < 0.0001) compared with the continent controls. In addition, there was a decreased ratio of type I to type III collagen (P = 0.0008), and the cross-link content was also significantly reduced in the women with genuine stress incontinence (P < 0.0001). Conclusion Genuine stress incontinence is present in a significant number of women before childbirth. The aetiology of their incontinence appears to be due to a defect in their connective tissue, with both a quantitative and qualitative reduction in their collagen.