PIP: 39 women were randomly allocated to contraception with either a combined oral contraceptive (ethinyl estradiol 37.5 mcg + lynestrenol 0.75 mg=EE + LYN), a progestin-only preparation (lynestrenol 0.5 mg daily=LYN), or a copper containing IUD. Pretreatment and 1, 3, and 6 month treatment blood samples were obtained and assayed for serum cholesterol, triglycerides, and high density lipoprotein (HDL) cholesterol. In the subjects using EE+LYN, the HDL cholesterol/cholesterol ratio was significantly (P0.01) elevated after 6 months treatment. Also, triglycerides increased significantly (P0.01). In the LYN group, no significant alterations in the lipid parameters occurred. In the IUD group, cholesterol levels decreased significantly (P0.05) and a significant (P0.01) rise in HDL-cholesterol/cholesterol ratio was seen. Triglyceride levels did not change. The results obtained suggest that the low-dose EE+LYN and LYN OCs do not induce such changes in serum lipids that could be related to the risk of development of atherosclerosis. The decrease in cholesterol levels during IUD use remains to be confirmed by other further studies.