Epidemiology of genital prolapse: Observations from the Oxford Family Planning Association Study

Objective To explore the epidemiology of uterovaginal and post-hysterectomy prolapse. Design Cohort study. Setting Seventeen large family planning clinics in England and Scotland. Population 17,032 women who attended family planning clinics between 1968 and 1974, aged between 25 and 39 years at study entry. Methods Annual follow up by interview, postal or telephone questionnaire until July 1994. Further details on all hospital admissions were obtained from the hospital discharge summaries. All women were flagged at time of recruitment in the NHS central registers. Main outcome measure In-patient admission with diagnosis of prolapse (ICD codes 8th Revision 623.0-623.9). Results The incidence of hospital admission with prolapse is 2.04 per 1000 person-years of risk. Age, parity, calendar period and weight were significantly associated with risk of an inpatient admission with prolapse after adjustment for principal confounding factors. Significant trends were observed with regard to smoking status and obesity (Quetelet Index) at entry to the study and risk of prolapse. Social class, oral contraceptive use and height were not significantly associated with risk of prolapse. The incidence of prolapse which required surgical correction following hysterectomy was 3.6 per 1000 person-years of risk. The cumulative risk rises from 1% three years after a hysterectomy to 5% 15 years after hysterectomy. The risk of prolapse following hysterectomy is 5.5 times higher (95% CI 3.1-9.7) in women whose initial hysterectomy was for genital prolapse as opposed to other reasons. Conclusion Among the potential risk factors that were investigated, parity shows much the strongest relation to prolapse.