Risk of oophorectomy after hysterectomy.

OBJECTIVE To compare the risk of subsequent oophorectomy among women who underwent hysterectomy for benign indications and those who did not. METHODS Using Rochester Epidemiology Project resources, we compared the risk of oophorectomy through December 31, 2008, among 4,931 women in Olmsted County, Minnesota, who underwent ovary-sparing hysterectomy for benign indications (case group) between 1965 and 2002, with 4,931 age-matched women who did not undergo hysterectomy (referent group). The cumulative incidence of subsequent oophorectomy was estimated by the Kaplan-Meier method, and comparisons were evaluated by Cox proportional hazard models using age as the time scale to allow for complete age adjustment. RESULTS The median follow-up times for case group and referent group participants were 19.6 and 19.4 years, respectively. At 10, 20, and 30 years after hysterectomy, the respective cumulative incidences of subsequent oophorectomy were 3.5%, 6.2%, and 9.2% among case group participants and 1.9%, 4.8%, and 7.3% among referent group participants. The overall risk of subsequent oophorectomy among case group participants was significantly higher than among referent group participants (hazard ratio [HR] 1.20, 95% confidence interval [CI] 1.02-1.42; P=.03). Furthermore, among case group participants, the risk of subsequent oophorectomy was significantly higher (HR 2.15, 95% CI 1.51-3.07; P<.001) in women who had both ovaries preserved compared with those who initially had one ovary preserved. CONCLUSION The incidence of oophorectomy after hysterectomy is only 9.2% at 30-year follow-up and is only 1.9 percentage points higher than the incidence of oophorectomy in referent women with intact reproductive organs. LEVEL OF EVIDENCE II.