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

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 estradiol/levonorgestrel 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 alpha-lipoprotein cholesterol only by ethinyl estradiol/desogestrel (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 estradiol/levonorgestrel and ethinyl estradiol/desogestrel increased apolipoproteins A (14%), A-I (20% to 30%), and A-II (25% to 35%) significantly. Very low-density lipoprotein triglycerides were elevated (30%) only by ethinyl estradiol/desogestrel, and low-density lipoprotein phospholipids (20%) by both ethinyl estradiol/levonorgestrel and ethinyl estradiol/desogestrel, whereas the other parameters, very low-density lipoprotein phospholipids, very low-density lipoprotein cholesterol, pre-beta-lipoprotein cholesterol, low-density lipoprotein triglycerides, low-density lipoprotein cholesterol, beta-lipoprotein cholesterol, and apolipoprotein B, were not significantly changed. Provided that the assumption is correct that high low-density 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.