The adverse effects of hormonal therapy.

Estrogen therapy must be cycled with progestin therapy in women with intact uteri in order to prevent uterine cancer. However, these women cannot be expected to benefit (with regard to cardiovascular disease) from any estrogen-induced changes in the lipoprotein profile, as progestins will either negate or overwhelm any estrogen effects. However, such women will definitely benefit from estrogen's effects with regard to menopausal symptoms and bone loss. These clearly beneficial effects of estrogen-progestin therapy are not outweighed by any known risks. However, in women without uteri (approximately 30 per cent of women), unopposed estrogen therapy in the menopause may protect against cardiovascular disease, as well as have beneficial effects on bone metabolism and menopausal symptoms. In this special case, the beneficial effects of unopposed estrogen therapy clearly outweigh any known risk.