Effects of levonorgestrel-releasing intrauterine system on glucose and lipid metabolism: a 1-year follow-up study

PURPOSE: This prospective study aimed to assess the possible effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) on serum lipids and fasting blood glucose levels over a period of 1 year. METHODS: Forty-eight premenopausal women, attending our gynecology clinic with the complaint of menorrhagia, were enrolled in the study. Systolic and diastolic blood pressures were recorded. Serum concentrations of total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), very low density lipoprotein cholesterol (VLDL-C), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and fasting plasma glucose (FPG) levels were tested before (pretreatment group) and 1 year later following insertion (on-treatment group). Baseline mean parameters were compared with mean parameters at 1 year for statistical significance using paired samples t-test. RESULTS: Thirty-three (68.75%) women were eligible for control in the on-treatment group. Mean age of the patients was 44.34+/-7.59 years. The study results showed that mean FPG level was significantly increased, whereas mean diastolic blood pressure was significantly decreased. Although mean systolic blood pressure tended to decrease and HDL-C concentrations to increase, these changes from baseline levels were insignificant. There were no significant changes in mean TG, TC, VLDL, LDL, AST and ALT. DISCUSSION: The only significant unfavorable effect observed was an increase in FPG level. Since it did not rise to risky values, but alerted us for the high risk patients for glucose intolerance before insertion. The LNG-IUS can be regarded as being safe in their effects on lipid metabolism, blood pressure and liver function tests.