This study examined the effects of hysterectomy, the second most common major operation performed in the United States, and oophorectomy, which is currently recommended for women aged 50 years and older, on sex hormone levels in 684 postmenopausal women who were not receiving estrogen. The subjects were white and lived in a middle to upper middle class community in southern California. Their mean age was 73 years, and nearly 90 percent were aged 65 and older. The average time since menopause was 26 years. Hysterectomy had been performed in 18 percent of women with conservation of one or both ovaries and with bilateral oophorectomy in another 18 percent.
Androstenedione levels were about 10 percent lower in women who had undergone hysterectomy than in intact women, regardless of the state of the ovaries. Levels of total and bioavailable testosterone were reduced by 29 percent in women who had hysterectomy alone and by 40 percent after bilateral oophorectomy. Compared with women whose ovaries were conserved, those undergoing bilateral oophorectomy had 30 percent lower testosterone levels (Fig. 1). Estradiol levels also tended to be lower after bilateral oophorectomy, but ovarian status did not influence levels of estrone or sex hormone–binding globulin (SHBG) or the estradiol/SHBG ratio. Testosterone levels increased with advancing age in intact women and reached premenopausal levels at age 70 to 79 years. No age variance was noted in oophorectomized women, whose testosterone levels were as much as 50 percent lower than in intact women from age 50 to 89 years. Levels of androstenedione decreased 27 percent with aging in intact women, and SHBG levels rose 30 percent. These changes were not evident in oophorectomized women. Similar results were obtained when analyzed by years since menopause or surgery rather than chronological age. None of the associations were altered when adjusted for alcohol consumption, current smoking status, or reported level of physical activity.
The ovary remains an important source of androgen in postmenopausal women. The sequelae of lowered testosterone levels in oophorectomized women, if any, are unclear. Prophylactic oophorectomy should be reconsidered and the effects of androgen replacement assessed in women being considered for this surgery.
J Clin Endocrinol Metab 2000;85:645–651
Department of Family and Preventive Medicine, Division of Epidemiology, University of California-San Diego, School of Medicine, La Jolla, California