The effect on carbohydrate and lipid metabolism of two hormonal contraceptive preparations containing norethisterone (commercially known as Mesigyna and TriNovum) was studied in a total of 60 women, before and after 6 months of treatment. Carbohydrate metabolism was evaluated by means of a euglycemic glucose clamp test; lipid metabolism was monitored by measuring total cholesterol, HDL-cholesterol, LDL-cholesterol, VLDL-cholesterol, and triglycerides. The two groups were properly matched with the exception of pretreatment levels of cholesterol and LDL-cholesterol. At the end of treatment, no difference was found within or between groups in fasting glucose and insulin levels and in glucose rate of disappearance A significant increase in total cholesterol, HDL-cholesterol, and VLDL-cholesterol was found in both groups at the end of the treatment period; in addition, TriNovum caused a significant increase also in triglycerides. In conclusion, the safety of both preparations with regard to carbohydrate metabolism was confirmed using the most accurate method available; furthermore, changes in lipid metabolism were such as to have little clinical significance. (C) 1997 Elsevier Science Inc. All rights reserved.