Effect of low-dose oral contraceptives on lipoproteins and lipolytic enzymes: differences between two commonly used preparations.

Changes in circulating lipoproteins, which may be related to the risk for atherosclerotic vascular disease, were studied in a control group and in two groups of 24 or 26 women using different preparations of low-dose oral contraceptives for 3 months. One preparation contained 150 micrograms levo-norgestrel and 30 micrograms ethinylestradiol (Stediril-d 150/30); the other contained 750 micrograms lynestrenol and 37.5 micrograms ethinylestradiol (Ministat). No significant changes were found with either of the preparations in serum cholesterol or high density lipoprotein cholesterol (HDL-C) levels. Apolipoprotein A-II levels increased during Ministat treatment from 50.4 to 61.4 mg/dL and during Stediril-d 150/30 treatment from 52.7 to 58.9 mg/dL (both P less than 0.001). These changes differed significantly from each other (P less than 0.01). Apolipoprotein A-I levels increased significantly during use of Ministat only. Apolipoprotein B in low density lipoprotein increased by about 20% (P less than 0.001) in both groups. Post-heparin lipoprotein lipase activity did not change, but hepatic lipase activity decreased to the same extent in both groups (P less than 0.001). Reductions in post-heparin lipase activity were not correlated with increases in HLD-C.