A randomized crossover comparison of two low-dose contraceptives: Effects on serum lipids and lipoproteins

Abstract

The effect of a triphasic combination of ethinyl estradiol and levonorgestrel upon various lipoprotein parameters was compared to that of a preparation that contained ethinyl estradiol and desogestrel on days 6, 11, 21, and 28 of a control cycle, the third cycle of treatment with either, ethinyl estradioll/evonorgestrel or ethinyl estradiol/desogestrel (11 volunteers each), the third cycle of a 3-month washout period, and the third treatment cycle after crossover change of the preparations. Significant increases were found in total triglycerides (15% to 20%) and phospholipids (8%) with both preparations, whereas total cholesterol and lipoprotein Lp(a) were not altered. High-density lipoprotein triglycerides (50% to 60%) and high-density lipoprotein-3 cholesterol (10% to 15%) were elevated by both contraceptives, high-density lipoprotein cholesterol and α-lipoprotein cholesterol only by ethinyl estradiolldesogestrel (11%), whereas high-density lipoprotein phospholipids, high-density lipoprotein-2 phospholipids, high-density lipoprotein-3 phospholipids, and high-density lipoprotein-2 cholesterol were not influenced. Both ethinyl estradioll levonorgestrel and ethinyl estradiolldesogestrel increased apolipoproteins A (14%c), A-I (20% to 30%), and A-II (25% to 35%) significantly. Very low-density lipoprotein triglycerides were elevated (30%) only by ethinyl estradiolldesogestrel, and low-density lipoprotein phospholipids (20%) by both ethinyl estradioll levonorgestrel and ethinyl estradiolldesogestrel, whereas the other parameters, very low-density lipoprotein phospholipids, very low-density lipoprotein cholesterol, pre-β-lipoprotein cholesterol, lowdensity lipoprotein triglycerides, low-density lipoprotein cholesterol, β-lipoprotein cholesterol, and apolipoprotein B, were not significantly changed. Provided that the assumption is correct that high lowdensity lipoprotein cholesterol and apolipoprotein B and low high-density lipoprotein subfractions and apolipoprotein A are associated with an elevated risk of atherosclerosis, the results seem to represent beneficial rather than deleterious side effects of the low-dose oral contraceptives.