Progestin enhances vasoconstrictor responses in postmenopausal women receiving estrogen replacement therapy.

Clinical and experimental evidence suggests that the cardioprotective effect of estrogen replacement is due to effects both on scrum lipids and on blood vessels. Current practice includes the use of a progestin in combination with estrogen if the patient still has her uterus: however, little is known about the effects of combination therapy on vascular reactivity. We therefore studied the effects of estrogen alone and with added progestin on forearm vascular resistance at rest, during reactive hyperemia, and after cold pressor stimulation using plethysmography in six healthy, postmenopausal women.