The clinical and biochemical effects of two combination oral contraceptive agents

A comparison of the effects of two low-dose oral contraceptives on lipid metabolism was undertaken in an open-group comparative design study at the Family Planning Clinic, Groote Schuur Hospital, Cape Town. Sixty healthy women aged 18-35 years requesting oral contraception were allocated alternately to use a monophasic oral contraceptive containing 30 micrograms ethinyloestradiol and 150 micrograms desogestrel (Marvelon, group A), or a triphasic oral contraceptive containing 30-40 micrograms ethinyloestradiol and 50-125 micrograms levonorgestrel (Triphasil, group B). The changes in the lipoprotein profile elicited by the two preparations differed significantly. Group A subjects had a much greater triglyceridaemic response (42.4%) than group B (14.6%) and had a significant increase in high-density lipoprotein cholesterol (HDL-C) and apolipoprotein A-1 (Apo-A1). In group B, HDL-C decreased and Apo-A1 showed little change. Non-HDL-C (NHDL-C) and Apo-B levels hardly changed in either group. The atherogenic ratios, NHDL-C/HDL-C and Apo-B/Apo-A1 were higher in group B. This study confirmed a significant difference in the response of plasma lipoproteins to the two oral contraceptive preparations. The evidence suggests that the desogestrel-containing oral contraceptive elicits a less atherogenic lipoprotein profile than does the levonorgestrel-containing preparation. Although unsupported by direct clinical evidence that changes in the lipoprotein pattern induced by oral contraceptives cause atherosclerosis, these effects should be considered when prescribing oral contraceptives for women who have risk factors for cardiovascular disease.