Anatomical and functional changes in the lower urinary tract following spontaneous vaginal delivery

Abstract

Objective: To assess the incidence of urinary incontinence in pregnancy and after spontaneous vaginal delivery and its relation with changes in the static and dynamic function of the pelvic floor.

Design: The second part of a prospective longitudinal study.

Setting: University Hospital Groningen and Martini Hospital Groningen, the Netherlands.

Population: A cohort of 62 women before and after spontaneous vaginal delivery at term and 27 nulliparous non-pregnant controls.

Methods: Urinary incontinence was measured by a questionnaire and by a 24 hour pad test. The position and mobility of the urethrovesical junction were measured by perineal ultrasound and related to simultaneously measured abdominal pressure changes. Serial investigations were done at 38 weeks of gestation and at 6 weeks and 6 months after delivery.

Main outcome measures: Urinary incontinence and its relation with the position of the urethrovesical junction at rest and with the mobility of the urethrovesical junction during Valsalva and during coughing, indicated by the displacement/pressure coefficient and with obstetric variables.

Results: After delivery, reported urinary incontinence was reduced from 26% at 38 weeks of gestation to 16% and 15% at 6 weeks and 6 months after delivery, respectively. Even lower rates were measured by the 24 hour pad test, which revealed a decrease from 14% at 38 weeks to 10% and 5% at 6 weeks and 6 months postpartum, respectively. Six weeks and six months after delivery, the angle of the urethrovesical junction at rest was significantly increased compared with the non-pregnant control women. Compared with the antenatal measurements, the displacement/pressure coefficients during coughing and during the Valsalva manoeuvre were significantly increased six weeks after delivery. Six months after delivery, only the coefficient for coughing was still significantly greater than the antenatal value and the value in the non-pregnant control group. No relations were found between urethrovesical junction measurements and obstetric variables and subjective or objective urinary incontinence parameters.

Conclusion: Although pregnancy and spontaneous vaginal delivery significantly increased the degree of bladder neck descent during coughing, urinary incontinence, quite common during pregnancy, occurs less frequently postpartum.