A cross-sectional study of the forearm bone density of long-term users of levonorgestrel-releasing intrauterine system

BACKGROUND: There are concerns about the effect of hormonal contraceptives on bone mineral density (BMD), but there is currently no information available on the effect of the levonorgestrel-releasing intrauterine system (LNG-IUS) on BMD. The objective of this study was to compare the BMD of LNG-IUS users with that of controls using the TCu380A intrauterine device (IUD). MATERIALS AND METHODS: A cross-sectional study paired 53 women, aged 25-51 years, who had been using the LNG-IUS for 7 years, with 53 IUD users, according to age (+/-1 year) and body mass index (BMI; kg/m2) (+/-1). BMD was evaluated at the midshaft of the ulna and the distal radius of the nondominant forearm using double X-ray absorptiometry. RESULTS: Mean age of women was 34 years. BMI was slightly over 25 in both groups. Estradiol was normal. Mean BMD was 0.469 +/- 0.008 and 0.467 +/- 0.009 and 0.409 +/- 0.009 and 0.411 +/- 0.009 at the midshaft of the ulna and distal radius in LNG-IUS and IUD users, respectively, without significant differences. CONCLUSIONS: Women aged 25-51 years, using the LNG-IUS for 7 years, had a mean BMD similar to that of the control group of TCu380A IUD users.