Effects of ethinyl-estradiol/noretisterone combinations on serum lipoproteins

Eleven healthy young women (age range 20-28 years) were given three different oral contraceptives (OCs) in random order, each contraceptive for 3 months. Smoking, eating, drinking and habits of physical activity were similar throughout the study period. The combinations were: ethinyl-estradiol/noretisterone (EE/NET) 35 micrograms/0.5 mg, 35 micrograms/1 mg and 50 micrograms/1 mg. The 35/0.5 and the 50/1 EE/NET combinations led to significant weight increases of 2.4 and 1.7 kg, respectively. All EE/NET combinations produced LDL-TG increases, from a pretreatment value of 0.28 +/- 0.04 (SD) mmol/l to 0.34 +/- 0.07, 0.35 +/- 0.06 and 0.42 +/- 0.13 mmol/l (P less than 0.01 for all). LDL-cholesterol increased from 2.99 +/- 0.63 mmol/l to 3.35 +/- 0.62 (P less than 0.01) after 35/1 treatment and to 3.43 +/- 0.62 mmol/l (P less than 0.001) after 50/1 treatment. These two EE/NET combinations also caused significant reductions of HDL-cholesterol, in both cases from a pretreatment value of 1.75 +/- 0.16 mmol/l to 1.64 +/- 0.24 mmol/l (P less than 0.05). Since all values after EE/NET treatment remained well within normal ranges, these low-dose OCs probably have little effect on the development of atherosclerosis due to serum lipoprotein abnormalities. However, our findings suggest that OCs may interfere with the cholesterol ester/TG exchange between LDL and HDL.