Transdermal estrogen reduces vascular resistance and serum cholesterol in postmenopausal women

Objective: Our aim was to compare the effects of transdermal versus oral estrogens on vascular resistance index, mean arterial pressure, serum lipid concentrations, norepinephrine, and left ventricular structure. Study Design: Ten postmenopausal women received transdermal estradiol (0.05 mg/d) plus cyclic oral progesterone for 6 months. Responses were compared with those of 23 women receiving oral conjugated estrogens (0.625 mg/d) plus cyclic progesterone and with those of 9 subjects receiving placebo in a concurrent randomized trial. We assessed the vascular resistance index and the mean arterial pressure at rest and during behavioral stressors. Results: Oral and transdermal estrogen significantly decreased the vascular resistance index, mean arterial pressure, norepinephrine, and total and low-density lipoprotein cholesterol to a similar extent. Changes in the vascular resistance index and mean arterial pressure were equally evident at rest and during stress. Although both treatments reduced left ventricular mass (–4% to –6%) and relative wall thickness (–3% to –5%), these changes were not statistically significant. Conclusions: Equivalent reductions in vascular resistance index, norepinephrine, mean arterial pressure, and cholesterol were observed with transdermal and oral estrogens. Future studies comparing novel hormone regimens with oral hormone replacement therapy should include multiple risk markers to allow better assessment of their potential impact on coronary artery health. (Am J Obstet Gynecol 2001;184:926-33.)