Absorption and metabolic effects of different types of estrogens and progestogens.

The classes of estrogens and progestogens currently in use and their routes of administration have been considered. The decision to prescribe any given estrogen or progestogen and by a particular route has a significant impact on cardiovascular risk factors. Among the estrogens, native estradiol and estrone are favored over equine and synthetic estrogens. Given this choice, oral and systemic routes of administration are not sufficiently different clinically to endorse one method over the other, except for the unusual hypertensive woman or the patient with a history of thromboembolic phenomena. Among the progestogens, oral micronized progesterone offers much promise for use in postmenopausal women. However, the oral use of lower doses of other progestogens seems appropriate at the present time. With the availability of oral micronized progesterone and in time a transdermal system, the need for alternate routes of administration for other progestogens seems unnecessary.