Bony pelvis dimensions in women with and without stress urinary incontinence

To test the null hypothesis that bony pelvis dimensions are similar in women with and without stress urinary incontinence (SUI), both in the postpartum and midlife periods.

Secondary analyses were performed of two case-control studies comparing women with SUI to asymptomatic controls. One study examined primiparas in the first 9-12 months postpartum; the other study involved middle-aged women. SUI was confirmed by full-bladder stress test. All subjects underwent pelvic magnetic resonance imaging. The interspinous and intertuberous diameters, subpubic angle, and sacrococcygeal joint-to-the inferior pubic point distance were measured from the images independently by two authors.

In the young cohorts, we compared primiparas with de novo postpartum SUI to both continent primiparas and nulliparas. Postpartum SUI is associated with a wider subpubic angle. There is also a trend towards wider interspinous and intertuberous diameters in the stress-incontinent primiparas as compared to the continent cohorts, although this did not reach statistical significance with our sample sizes. By contrast, no significant differences in bony pelvis dimensions were identified when comparing middle-aged women with SUI and their continent controls.

Bony pelvis dimensions are different in women with SUI than in matched continent controls. However, these differences are only identified in young primiparas in the postpartum period, not in middle-aged women.