Changes in bone mineral density of users of the levonorgestrel-releasing intrauterine system

The aim of this study was to evaluate changes in bone mineral density (BMD) in patients using a levonorgestrel-releasing intrauterine system (LNG-IUS) or a TCu380A intrauterine device (IUD) after 2 years.

The medical records of all patients who underwent LNG-IUS (n=38) or TCu380A IUD (n=26) insertion from May 2006 through December 2010 were reviewed. The patients were 40 to 45 years old at the time of insertion, had undergone a BMD examination of the femur and lumbar spine before the loop insertion, and had also received a follow-up BMD examination 2 years later. Patients were excluded if risk factors known to affect BMD were noted in their medical records. The 2 groups of patients were compared with regard to age, parity, body-mass index (BMI), and levels of osteocalcin and pyridinoline. Changes in BMI, osteocalcin, and pyridinoline after 2 years were also compared.

The LNG-IUS and TCu380A IUD groups showed no differences in mean age, mean parity, mean BMI, preinsertion or postinsertion BMD values of the femur or lumbar spine, changes after 2 years in the BMD of the femur or lumbar spine, or changes after 2 years in osteocalcin or pyridinoline level (P>0.05).

Women using the LNG-IUS for 2 years have changes in BMD and osteocalcin and pyridinoline levels similar to those of TCu380A IUD users. The use of the LNG-IUS for 2 years may have no adverse effect on BMD.