Many women who take hormone treatment after surgically induced menopause report getting relief similar to that experienced by women who take hormones after natural menopause. Specifically, many women report fewer episodes of hot flashes and night sweats. Researchers have also found that younger women who report memory loss after a hysterectomy do better on some cognitive tests after beginning to take estrogen, but we don't know whether this is truly an effect of the estrogen or whether it might be explained by other factors. For older women, the research evidence is clear: the Women's Health Initiative (WHI) found that taking estrogen increased the risk for dementia in women over 65 who have had a hysterectomy.
Little research has examined the health risks of taking hormones for those of us who have had the ovaries removed. The WHI provides some data that is relevant, since all of the women in the estrogen-only part of the study had a hysterectomy, though some of them still had their ovaries. The WHI found that hormone treatment increased the risk of stroke in women who had a hysterectomy. The WHI also indicated that in colorectal cancer or a heart attack, there was neither a risk nor a benefit for these women and the effect of hormone treatment on blood clots and breast cancer for these women was uncertain. It is important to note, however, that for women whose ovaries were removed specifically to treat cancer, the risk of either recurrent cancer or other cancers associated with hormone treatment may be greater than for other women.