The global burden of female pelvic floor disorders

Genetic influence on stress urinary incontinence and pelvic organ prolapse

OBJECTIVES

To determine the genetic and environmental influence on the liability for stress urinary incontinence and pelvic organ prolapse surgery.

METHODS

We used the Swedish Twin Registry to identify all same-sex female twin pairs with known zygosity born from 1926 to 1958. Occurrence of stress urinary incontinence and pelvic organ prolapse surgery was determined by cross-linkage to the Swedish Inpatient Registry. By comparing mono- and dizygotic female twins, we determined twin similarity and the relative proportions of phenotypic variance resulting from genetic and environmental factors. Using statistical modelling, the liability for pelvic floor surgery explained by heritability versus shared and non-shared environmental effects was estimated.

RESULTS

We identified 3376 complete monozygotic and 5067 dizygotic same-sex female twin pairs. There was greater twin similarity among monozygotic compared with dizygotic twins, which indicates the influence of a genetic component to the aetiology of both stress urinary incontinence and pelvic organ prolapse surgery. For both disorders, genetic and non-shared environmental factors equally contributed about 40% of the variation in liability. Shared environment accounted for approximately one fifth of the total variance for the two disorders.

CONCLUSIONS

Genetic effects contribute to the occurrence of both stress urinary incontinence and pelvic organ prolapse, but the influence of environmental factors is substantial. Significant environmental effects suggest that the liability for benign pelvic floor surgery is amenable to intervention.

Symptoms of anal and urinary incontinence following cesarean section or spontaneous vaginal delivery

OBJECTIVE

The objective of the study was to compare the prevalence of incontinence disorders in relation with spontaneous vaginal delivery or cesarean section.

STUDY DESIGN

Two hundred women with spontaneous vaginal deliveries only were compared with 195 women with cesarean deliveries only 10 years after first delivery.

RESULTS

When compared with cesarean section, vaginal delivery was associated with an increased frequency of stress urinary incontinence (P = .006) and an increased use of protective pads (P = .008) as well as an increased frequency of fecal urgency (P = .048) and gas incontinence (P = .01). At multivariate regression analysis, mode of delivery showed no significant association with incontinence symptoms other than an increased risk for flatus incontinence in women with a history of obstetric anal sphincter injury (odds ratio 3.1; 95% confidence interval, 1.5 to 8.9).

CONCLUSION

Incontinence symptoms are more common following spontaneous vaginal delivery when compared with cesarean section 10 years after first delivery. However, cesarean section is not associated with a major reduction of anal and urinary incontinence.

Hysterectomy and risk of stress-urinary-incontinence surgery: nationwide cohort study

BACKGROUND

Hysterectomy for benign indications has been associated with an increased risk for lower-urinary-tract sequela, but results have been inconclusive. We aimed to establish the risk for stress-urinary-incontinence surgery after hysterectomy for benign indications.

METHODS

We did a nationwide, population-based, cohort study from 1973 to 2003 in Sweden. We identified our population from the Swedish Inpatient Registry. We selected 165 260 women who had undergone hysterectomy (exposed cohort) and a control group of 479 506 individuals who had not had this procedure (unexposed cohort), matched by year of birth and county of residence. In both cohorts, occurrence of stress-urinary-incontinence surgery was established from the Swedish Inpatient Registry. Hazard ratios with 95% CIs were calculated by Cox's proportional-hazards regression.

FINDINGS

During the 30-year observational period, the rate of stress-urinary-incontinence surgery per 100,000 person-years was 179 (95% CI 173-186) in the exposed cohort versus 76 (73-79) in the unexposed cohort. Correspondingly, individuals in the exposed cohort were at increased risk for stress-urinary-incontinence surgery compared with those in the unexposed cohort (hazard ratio 2.4; 95% CI 2.3-2.5), irrespective of surgical technique. Risk for stress-urinary-incontinence surgery varied slightly with time of follow-up: the highest overall risk was recorded within 5 years of surgery (2.7; 2.5-2.9) and the lowest risk was seen after an observation period of 10 years or more (2.1, 1.9-2.2).

INTERPRETATION

Hysterectomy for benign indications, irrespective of surgical technique, increases the risk for subsequent stress-urinary-incontinence surgery. Women should be counselled on associated risks related to hysterectomy, and other treatment options should be considered before surgery.

Planned cesarean section versus planned vaginal delivery: comparison of lower urinary tract symptoms

We compared the prevalence and risk of lower urinary tract symptoms in healthy primiparous women in relation to vaginal birth or elective cesarean section 9 months after delivery. We performed a prospective controlled cohort study including 220 women delivered by elective cesarean section and 215 by vaginal birth. All subjects received an identical questionnaire on lower urinary tract symptoms in late pregnancy, at 3 and 9 months postpartum. Two hundred twenty subjects underwent elective cesarean section, and 215 subjects underwent vaginal delivery. After childbirth, the 3-month questionnaire was completed by 389/435 subjects (89%) and the 9-month questionnaire by 376/435 subjects (86%). In the vaginal delivery cohort, all lower urinary tract symptoms increased significantly at 9 months follow-up. When compared to cesarean section, the prevalence of stress urinary incontinence (SUI) after vaginal delivery was significantly increased both at 3 (p < 0.001) and 9 months (p = 0.001) follow-up. In a multivariable risk model, vaginal delivery was the only obstetrical predictor for SUI [relative risk (RR) 8.9, 95% confidence interval (CI) 1.9-42] and for urinary urgency (RR 7.3 95% CI 1.7-32) at 9 months follow-up. A history of SUI before pregnancy (OR 5.2, 95% CI 1.5-19) and at 3 months follow-up (OR 3.9, 95% CI 1.7-8.5) were independent predictors for SUI at 9 months follow-up. Vaginal delivery is associated with an increased risk for lower urinary tract symptoms 9 months after childbirth when compared to elective cesarean section.

Seeking healthcare for pelvic floor disorders: a population-based study

OBJECTIVE

The purpose of this study was to identify characteristics that are associated with seeking care for pelvic floor disorders (PFD).

STUDY DESIGN

Strategies for seeking care for pelvic organ prolapse, urinary incontinence (UI), and anal incontinence (AI) were assessed in 4392 women. Women were dichotomized into women who had sought care and women with disorders who had not. Chi-square and t tests were used to compare demographic and medical variables. Logistic regression was used to calculate adjusted odds ratios (ORs) with 95% CI.

RESULTS

Women who sought care were significantly older (64 +/- 13.1 vs 55 +/- 14.8 years old; P < .001). After an adjustment for significant variables, care-seeking was associated with increasing age per year (prolapse OR, 1.07 [95% CI, 1.04-1.11]; UI OR, 1.04 [95% CI, 1.02-1.05]), hysterectomy (prolapse OR, 4.30 [95% CI, 2.16-8.55]; UI OR, 1.40 [95% CI, 1.05-1.89]), hormone replacement (UI OR, 1.78 [95% CI, 1.29-2.45]), and urinary infections (AI OR, 1.67 [95% CI, 1.04-2.68]).

CONCLUSION

Seeking care for PFD is associated with older age, hysterectomy, hormone use, and frequent urinary tract infection. This reinforces the need for PFD treatment as our population ages and demand increases.

Deformation of the pelvic floor muscles during a vaginal delivery

Pelvic floor dysfunction is a hidden problem with a magnitude unknown to many. Statistics show that one in every ten women will have pelvic floor dysfunction so severe that it will require surgery. Several studies have shown that pelvic floor injuries during a vaginal delivery can be considered a significant factor in the development of urinary incontinence, fecal incontinence, and pelvic organ prolapse. The objective of the present work is to contribute to the clarification of the mechanisms behind pelvic floor disorders related to a vaginal delivery. For this purpose, a numerical simulation based on the finite element method was carried out. The finite element model intends to represent the effects that the passage of a fetal head can induce on the muscles of the pelvic floor, from a mechanical point of view. The model used for the simulation represents the pelvic bones, with the attached pelvic floor muscles and the fetus. In this work, we simulated the movements of the fetus during birth, in vertex position. We simulated the engagement, descent, flexion, internal rotation, and extension of the fetal head. Results for the pelvic floor stretch values obtained during the passage of the fetus head are presented; the deformation field is also shown. The results were obtained using the finite element method and a three-dimensional computer model of the pelvic floor and fetus. The maximum deformation obtained was 0.66 for a vertical displacement of the fetal head of approximately 60 mm.