Intrauterine administration of levonorgestrel in two low doses in HRT. A randomized clinical trial during one year: effects on lipid and lipoprotein metabolism

Objective: To investigate the effects on lipid and lipoprotein metabolism of two doses (5- or 10 μg/24 h) of levonorgestrel released from an intrauterine device (IUD) in combination with orally administered estradiol (2 mg estradiol valerate) in perimenopausal women. Design: A 1-year prospective randomized single blind clinical trial. setting: Department of Obstetrics and Gynaecology, Östra Hospital, Göteborg, Sweden. Subjects: Fifty-one perimenopausal women with climacteric symptoms. Outcome measures: Cholesterol in serum and in lipoprotein fractions; high-density lipoprotein 9HDL), low-density lipoprotein (LDL). Triglycerides in serum and in very low-density lipoprotein. Results: In both treatment groups significant elevations in HDL-cholesterol of similar magnitude were observed after 1 month and these changes were maintained during the 12 month observation period. In both treatment groups an initial significant decrease of LDL-cholesterol was observed and the decrement was maintained after 12 months. Serum levels of cholesterol decreased significantly in both groups after 1 month and were maintained after 12 months in the levonorgestrel-IUD (LNG-IUD) 5 μg group. However, the initial reduction of serum cholesterol in the LNG-IUD 10 μg group did not differ from baseline after 12 months. Serum triglyceride levels fluctuated during the observation period. No significant changes occurred. Conclusion: continuous combined HRT with intrauterine administration of levonorgestrel, 5- or 10 μg/24 h, in perimenopausal women was observed to increase HDL-cholesterol and to decrease LDL-cholesterol compared with pretreatment values. the low doses of levonorgestrel did not reverse the beneficial effects on lipid metabolism usually seen after estradiol administration.