Prevalence of Low Bone Mass and Osteoporosis in Long-Term Users of the Injectable Contraceptive Depot Medroxyprogesterone Acetate

Abstract

Background: Bone mineral density (BMD) loss among depot medroxyprogesterone acetate (DMPA) users is a controversial issue. Aspects under debate include whether the number of years of use has any effect on continuous BMD loss, whether this loss will stabilise over the years of use or if it will progress to low bone mass, osteoporosis and an increased fracture risk. The aim of this study was to compare the difference in osteoporosis and low bone mass between DMPA and copper intrauterine device (Cu-IUD) users.

Methods: This was a cross-sectional study that evaluated BMD at the lumbar spine and femoral neck in 47 long-term DMPA users and 41 Cu-IUD users as control group. BMD was measured by dual-energy X-ray absorptiometry. The participants were 27 to 57 years of age, had used either DMPA or a Cu-IUD uninterruptedly for at least ten years, had initiated use of the method prior to 40 years of age and had follicle stimulating hormone values <40 mIU/mL.

Results: Findings showed that 68.1% and 36.6% of the DMPA and Cu-IUD users, respectively, had low bone mass and 29.8% and 2.4% of DMPA and Cu-IUD users, respectively, had osteoporosis. BMD decreased as the number of years of DMPA use increased.

Conclusion: Long-term DMPA use was associated with low bone mass and osteoporosis in women who had used the method for 10 years or more. DMPA users with longer time of use showed a greater bone mass loss.