The effects of birth on urinary continence mechanisms and other pelvic-floor characteristics

Objective: To determine the effects of delivery on bladder and anorectal functions. Methods: One hundred forty-nine nulliparas were studied once during pregnancy and again about 9 weeks after delivery by means of questionnaire, clinical examination, perineal sonography, urethral pressure profiles, and recording of intravaginal and intra-anal pressures during pelvic-floor contraction. Results: Stress urinary incontinence was present in 46 patients (31%) during pregnancy and persisted in ten of them after delivery. After vaginal delivery, urinary and fecal incontinence were present in 36% and 4% of forceps-delivered women, respectively, and in 21% and 5.5% of spontaneously delivered women. Bladder neck mobility was increased significantly after all vaginal births, whereas bladder neck position at rest was lowered only in forceps-delivered women. Functional urethral length was decreased in the supine and standing positions after spontaneous and forceps deliveries. Otherwise, indices of urethral sphincter function were unchanged or improved after vaginal delivery. A significant decrease in intravaginal pressure and in intra-anal pressure was observed in all vaginally delivered women. The intra-anal pressure decrease correlated significantly with infant weight (r = 0.24, P = .01). Women who underwent cesarean had no specific complaints and only slight modifications of these measurements. Conclusion: After spontaneous and instrumental deliveries, 21% and 34% of women complained of stress urinary incontinence and 5.5% and 4% reported fecal incontinence, respectively. Substantial bladder neck hypermobility was present together with diminished functional urethral length and intravaginal and intra-anal pressures. Only 22% of patients with stress urinary incontinence during pregnancy had such incontinence after delivery. (Obstet Gynecol 1998; 92:613-8. (C) 1998 by The American College of Obstetricians and Gynecologists.).