Effects of oral contraceptives on lipid metabolism.

A randomized, comparative study of two low-dose oral contraceptives was carried out in 60 nonpregnant women for 12 cycles. Twenty-eight women took a preparation containing 150 micrograms of desogestrel and 30 micrograms of ethinyl estradiol; 32 took 75 micrograms of gestodene and 30 micrograms of ethinyl estradiol. Baseline values in the two groups were in good agreement. During the first three cycles, serum cholesterol levels remained unchanged, but triglyceride and high-density lipoprotein cholesterol levels increased significantly and to the same extent (about 20%). Low-density lipoprotein cholesterol levels decreased slightly. Apolipoproteins A1 and A2 and low-density lipoprotein B increased significantly and similarly. Except for continued increases in low-density lipoprotein B, no further changes were noted during subsequent cycles. We concluded that the two contraceptives have the same impact on lipid metabolism, with all lipid and apolipoprotein values remaining within the normal range. The changes with both pills reflect a mild estrogenic dominance. Implications for coronary artery atherosclerosis appear to be minimal.