EFFECTS OF ETHINYL ESTRADIOL COMBINED WITH DESOGESTREL AND CYPROTERONE-ACETATE ON GLUCOSE-TOLERANCE AND INSULIN-RESPONSE TO AN ORAL GLUCOSE-LOAD - A ONE-YEAR RANDOMIZED, PROSPECTIVE, COMPARATIVE TRIAL

To investigate the effects of two slightly estrogen-dominant, monophasic, low-dose oral contraceptives on carbohydrate metabolism, 40 healthy young women were randomly allocated to recelve either 30 μg of ethinyl estradiol + 150 μg of desogestrel, a 19-nortestosterone-derived progestin (Marvelon; n = 21) or 35 μg of ethinyl estradiol + 2 mg of cyproterone acetate, a 17-acetoxyprogesterone derivative (Diane-35; n = (19) for a prospective observation period of 1 year. At baseline, 6, and 12 months, blood glucose, plasma insulin, and plasma C-peptide levels were measured during an oral glucose tolerance test. Although the changes were absent (Marvelon) or minimal (Diane-35) at 6 months, both groups had a slight increase in blood glucose levels at 12 months; overall glucose tolerance remaining, however, within the normal range. Plasma insulin levels remained unchanged in the Diane-35 group, which suggested increased insulin resistance, but were significantly decreased in the Marvelon group despite significant rises in plasma C-peptide levels. Comparison of plasma C-peptide and insulin changes suggests enhanced pancreatic insulin secretion and increased hepatic insulin metabolism with both Marvelon and Diane-35. © 1990.