Prevalence of and Risk Factors for Urinary Incontinence During the Third Trimester and First Postpartum Year in Primiparous Women

OBJECTIVES: To identify the prevalence of and risk factors for urinary incontinence (UI) during the antenatal period and postpartum year in primiparous women.

DESIGN: A longitudinal, prospective, repeated measures and cohort study.

SETTING: Wirral University Teaching Hospital NHS Foundation Trust.

PARTICIPANTS: Primiparous women with no preexisting disease (N = 516) recruited after a normal 20-week obstetric ultrasound scan.

METHOD: Data were collected in the last trimester of pregnancy and at 6 weeks, at 6 months, and at 1 year postpartum using validated questionnaires. Obstetric data were extracted from case notes.

MAIN OUTCOME MEASURES: UI symptoms.

RESULTS: Stress incontinence during the third trimester was reported by 39.7% (n = 185) of the women participating in the study. At 6 weeks postpartum, 28.2% (n = 114); at 6 months postpartum, 31% (n = 123); and at 1 year postpartum, 26.5% (n = 89) of participants also reported stress incontinence.

Urge incontinence was reported by 23.5% (n = 110) of participants in the third trimester, 21.2% (n = 86) at 6 weeks postpartum, 21.4% (n = 85) at 6 months postpartum, and 16.4% (n = 55) at 1 year postpartum.

Women younger than 20 years old had higher rates of postpartum urge incontinence (p < .001) possibly associated with increased rates of infection. Body mass index (BMI) > 30 was associated with higher rates of antenatal stress incontinence but was not significant in the postpartum period. BMI < 20 was associated with an increase in postpartum urge incontinence. Prolonged periods in labor without bladder emptying was associated with increased rates of UI (odds ratio [OR] = 2.36). Forceps delivery was associated with postpartum stress incontinence (OR = 2.41). Although cesarean section appeared protective against UI initially, long-term data show a progressive increase in reported rates of UI even after elective cesarean section. Perineal trauma was associated with UI throughout the postpartum year with those women having anal sphincter disruption with the highest rates of stress incontinence (p < .005). Birth weight, duration of labor, feeding method, epidural anesthesia, and smoking were not significant. Overall, UI appears to be a regressive condition. Some participants had a progressive, deteriorating condition, which appears to be associated with a higher BMI or > 6 hours from bladder emptying to delivery of the newborn.

CONCLUSION: There are several identifiable risk factors that increase the prevalence and/or severity of UI symptoms.