Time Trends in Unilateral and Bilateral Oophorectomy in a Geographically Defined American Population

OBJECTIVE: To evaluate trends in the incidence of premenopausal unilateral and bilateral oophorectomy between 1950 and 2018. METHODS: The Rochester Epidemiology Project medical records–linkage system was used to identify all women aged 18–49 years who were residents of Olmsted County, Minnesota, and underwent unilateral or bilateral oophorectomy before spontaneous menopause between January 1, 1950, and December 31, 2018. Population denominators were derived from the U.S. Decennial Censuses for the years 1950–2010, and intercensal year population denominators were linearly interpolated. For 2011–2018, the annual population denominators were obtained from the U.S. Census projections. Where appropriate, overall incidence rates were age-adjusted to the total U.S. female population from the 2010 Census. RESULTS: There were 5,154 oophorectomies in Olmsted County across the 69-year period between 1950 and 2018, and 2.9% showed malignant disease on pathology. A total of 2,092 (40.6%) women underwent unilateral oophorectomy, and 3,062 (59.4%) women underwent bilateral oophorectomy. More than half (n=1,750, 57.2%) of the bilateral oophorectomies occurred between 1990 and 2009. Until 1975–1979, the incidence of unilateral oophorectomy was mostly higher than bilateral oophorectomy. From 1980–1984 until 2000–2004, the incidence of bilateral oophorectomy more than doubled and the incidence of unilateral oophorectomy declined. After 2005, both procedures declined and converged to a similar incidence in 2015–2018. The decline in premenopausal bilateral oophorectomy over the past 14 years (2005–2018) was most pronounced for women who underwent oophorectomy concurrently with hysterectomy or did not have any ovarian indication. CONCLUSION: The incidence rates of unilateral and bilateral oophorectomy have varied greatly across the 69-year period of this study. In the past 14 years, the incidence of premenopausal unilateral and bilateral oophorectomy has decreased. These trends reflect the effects of the initial 2005–2006 publications and the subsequent expanding body of evidence against the practice of oophorectomy for noncancer indications.