The Effect of Oral Contraceptives on Calcium Absorption
An impressive body of experimental and clinical evidence has accumulated which describes the effects of pharmacological and physiological doses of estrogens and progestogens on calcium and bone metabolism in man. One of the most obvious and glaring observations in this regard is that cyclic therapy of prepubertal subjects with estrogens and progestogens leads to a marked acceleration of epiphysial closure and linear growth with a resultant telescoping of the skeletal growth pattern. Accordingly, the present extensive use of various estrogenic-progestational combinations for the purpose of contraception warrants an objective review of the effects of prolonged therapy with these agents on calcium and mineral metabolism in man. This analysis should include not only any evaluation of hormonal effects in the younger menstruating (and presumably contraceptive prone) population, but also in the older post-menopausal patient since the so-called “oral contraceptive agents” have recently been advocated (and used) for the “therapy” of symptomatic osteoporosis. Subsequent reviews in this symposium will be concerned with the nature and extent of bone mineral and osteoid changes as well as the alterations in calcium and phosphorus homeostasis observed during intervals characterized by increasing circulating levels of estrogens and progestogens. Intrinsic to any scheme proposed to account for these effects is a knowledge of the effects of estrogens and/or progestogens on the intestinal absorption of calcium.
KeywordsEstrogen Therapy Ethinyl Estradiol Estradiol Valerate Calcium Phosphorus Epiphysial Closure
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