Comparison of the metabolic effects of two hormonal contraceptive methods: an oral formulation and a vaginal ring. II. Serum lipoproteins and apolipoproteins.

In a long-term, prospective study the effects on lipoprotein lipids and apolipoproteins (apo) of a combined oral contraceptive (OC) (30 micro gram ethinylestradiol and 150 micro gram levonorgestrel) and a contraceptive vaginal ring (CVR) releasing estradiol (about 180 micro gram per day) and levonorgestrel (about 290 micro gram per day) were compared. The two treatments induced significantly different effects. In the OC group the lipoprotein-lipid concentrations showed only minor changes, but apolipoproteins (apo) B and A-I increased by about 15%. In contrast, during treatment with the CVR there was a 25% decrement of cholesterol in high density lipoprotein (HDL) and at most 10% in low density lipoprotein (LDL) cholesterol, with only minor effects on apo B and A-I. The ratio of LDL and HDL cholesterol increased in the CVR group but not in the OC group. The results also indicate a change in the composition of the LDL and HDL particles, with an altered lipid/protein ratio, during both contraceptive treatments. Despite the impressive relative increase in LDL:HDL ratio in the contraceptive ring group, the average absolute value of this ratio did not reach the mena for healthy men.