Comparison of transdermal and oral estrogen-progestin replacement therapy: effects on serum lipids and lipoproteins

We attempted to ascertain whether transdermal postmenopausal estrogen-progestin therapy has the typical effects of oral therapy on serum lipoprotein risk markers for cardiovascular disease.

Sixty-one postmenopausal women were randomized to receive either transdermal continuous 17 beta-estradiol, 0.05 mg/day, with transdermal cyclic norethindrone acetate, 0.25 mg/day, or oral continuous conjugated equine estrogens, 0.625 mg/day, with oral cyclic dl-norgestrel, 0.15 mg/day. Twenty-nine untreated subjects served as controls. Lipoprotein profiles at 3 and 6 months were compared with baseline values by means of analysis of variance.

In the estrogen-alone phase both therapies reduced serum levels of total and low-density lipoprotein cholesterol; high-density lipoproteins were largely unchanged. Oral therapy increased triglycerides whereas this lipid fell with transdermal therapy. In the combined phase of the cycle both therapies reduced triglycerides, total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol.

Transdermal and oral therapies had similar effects on lipoprotein cholesterol but different effects on triglycerides.