Bone marrow allograft rejection by cytotoxic T-lymphocytes

Abstract

Widespread use of oral contraceptive formulations by women throughout their reproductive life has given rise to concerns about the effects of oral contraceptives on risk factors for coronary heart disease. Oral contraceptive-induced changes in both carbohydrate and lipoprotein risk factors may contribute to an increased risk of coronary heart disease. Carbohydrate and lipoprotein risk factors for coronary heart disease are reviewed, and oral contraceptive-induced changes in carbohydrate and lipoprotein metabolism, which may lead to altered risk status for coronary heart disease, are discussed. The importance of methodology in evaluating the results of studies assessing such oral contraceptive-induced changes is stressed. The role of progestins in influencing coronary heart disease risk factors is surveyed, and differences among progestins commonly used in oral contraceptive formulations are discussed. In addition, the effect of various combination oral contraceptives on risk factor status is outlined. Finally, the implications of available evidence for the selection of progestins for oral contraceptive formulations of the future are discussed. Current data indicate that medium- and low-fixed-dose oral contraceptive formulations containing estrogen/norethindrone acetate have less metabolic impact than do comparable levonorgestrel-containing formulations, including multiphasic formulations. Triphasic formulations may have less effect on coronary heart disease risk factors, although data are not yet conclusive. Novel progestins such as desogestrel may also have lesser effects on metabolic functions, but the reduced androgenicity of such compounds may expose women to an increased risk of estrogen-induced hypertriglyceridemia.