A pilot study examining short-term changes in bone mineral density among class 3 obese users of depot-medroxyprogesterone acetate

ABSTRACT

Objective To examine changes in lumbar spine-bone mineral density (LS-BMD) among normal weight (body mass index [BMI] = 18.5–24.9 kg/m²), Class 1–2 obese (BMI = 30–39.9 kg/m²), and Class 3 obese (BMI ≥ 40 kg/m²) women utilising depot-medroxyprogesterone acetate (DMPA).

Methods Five normal-weight, five Class 1–2 obese, and five Class 3 obese women received subcutaneous injections of DMPA-SC at baseline and 12 weeks later. Dual Energy X-ray Absorptiometry (DEXA) scans were performed at baseline and 18 weeks after the first injection for determination of LS-BMD and analysis of fat content. Bimonthly oestradiol (E₂) levels were measured by immunoassay methods for 26 weeks.

Results There were no significant demographic or LS-BMD differences among the three BMI groups. Significant differences at baseline were as expected among the three groups with respect to BMI and associated parameters (mean % total body fat, absolute fat, and weight). When used as their own controls, significant changes in LS-BMD, % body fat and absolute fat determined by DEXA occurred among all three BMI strata. Class 1–2 obese and Class 3 obese women were more likely to experience E₂ fluctuations, but short-term changes in LS-BMD were similar.

Conclusions DMPA-SC administration affects L-spine bone health similarly regardless of BMI status.

Keywords:

• Depot-medroxyprogesterone acetate
• Contraception
• Injectable
• Obese
• Class 3 obese
• Dual Energy X-ray Absorptiometry
• Bone mineral density

ACKNOWLEDGEMENTS

We would like to thank an anonymous donor for funding. We extend our appreciation to the clinicians and staff in the Reproductive Research Clinic and General Clinical Research Center (now Clinical Trials Unit) who participated in the implementation of this study. We also acknowledge the support of the University of Southern California GCRC (M01-RR-00043) for in-kind donations of administrative, technical and laboratory support. We are indebted to the USC Reproductive Endocrine Laboratory for their support.

Declaration of interest: The authors report no conflict of interest. The authors alone are responsible for the content and the writing of the paper.