EFFECT OF NORETHISTERONE AND LEVONORGESTREL IN LOW-DOSE MULTIPHASIC ORAL-CONTRACEPTIVES ON SERUM-LIPIDS

In a parallel, multicenter study in Norway and Finland involving a tot al of 196 healthy women (mean age 22.4 years, range 18-30), the effect s on serum lipids and lipoproteins of two multiphasic oral contracepti ves containing ethinyl estradiol (EE) but different progestins were ex amined. One formulation contained EE 35 mug and norethisterone (NET) 0 .5 mg on days 1-7 and days 17-21 and elevated NET 1.0 mg during the mi dphase (days 8-16). The other formulation contained EE 30 mug on days 1-6 and days 12-21 and 40 mug on days 7-11 and phased levonorgestrel ( LGN): 50 mug (days 1-6), 75 mug (days 7-11) and 125 mug (days 12-21). Both formulations induced significant elevation of total cholesterol ( 6.7 and 4.1%), Apo B (8.1 and 7.0%) as well as HDL (6.4 and 3.7%) for the EE/NET and EE/LGN formulation respectively. Mean serum levels of t riglycerides were significantly elevated (58 and 47%). However, all me an serum lipid and lipoprotein values remained within the normal range , and no change in the calculated cholesterol ratio (HDL/total cholest erol) nor lipoprotein ratio (HDL/(HDL + LDL)) was observed. No signifi cant difference between the formulations could be detected with respec t to the effect on serum lipids and lipoproteins measured. The change in total cholesterol was smaller than reported in many studies of mono phasic preparations. Taken together, these data suggest that only smal l alterations in lipid metabolism are elicited by these oral contracep tives.