When women have hysterectomies, their ovaries continue to make estrogen, according to WebMD. However, a hysterectomy is often paired with an oophorectomy, or removal of the ovaries. In this case, estrogen production drops dramatically.
Surgeons sometimes remove the ovaries without performing a hysterectomy, but it is not common, WebMD explains. In any case, when a woman's undergoes an oophorectomy, she develops surgical menopause. The drop in estrogen levels is sudden, so symptoms of menopause are severe. Doctors often recommend hormone therapy to help deal with the symptoms.
Women who have had both hysterectomies and oophorectomies receive estrogen replacement therapy, notes WebMD. However, an oophorectomy alone calls for both estrogen and progestin. Progestin reduces the risk of uterine cancer caused by estrogen therapy.