Oral contraceptives: hormonal dose and effects on carbohydrate metabolism

Abstract

The progestational components of combined oral contraceptives induce a hyperinsulinemic response to glucose challenge, due either to a decrease in insulin receptor binding or to a postreceptor defect in cellular insulin action. This effect on glucose metabolism poses no heightened risk of diabetes in normal young women, but in women who have had previous gestational diabetes and in women over 35 there is increased risk of deteriorated glucose tolerance. Studies using a monophasic and triphasic ethinyl-estradiol/levonorgestrel combination for 6 months have shown that the triphasic preparation, which contains 40% less progestagen during 1 cycle, prevents the hyperinsulinemic response to glucose in both normal women and women with previous gestational diabetes. Since deteriorated glucose metabolism is associated with insulin-induced inhibition of lipolysis and synthesis of cholesterol and triglycerides in arterial tissue and ultimately with the development of arterial fatty streaks, it is advisable to use combined oral contraceptives with the lowest effective doses of estrogens and progestagens.