Common Questions
How does depot medroxyprogesterone (DMPA) cause bone loss?
DMPA's affect on bone density is thought to be due to estrogen deficiency. Estrogen is involved in bone health by:
- Stimulating bone formation by direct action on osteoblasts (bone-producing cells)
- Increasing TGF-b, which seems to inhibit osteoclasts (bone-resorbing cells)
- Directly acting on osteoclasts by inhibiting their function and promoting apoptosis
- Directly affecting bone angiogenesis
Medroxyprogesterone suppresses the hypothalamic-pituitary-ovarian axis resulting in a suppression of ovulation. This leads to a relative hypo-estrogenic state, which resembles the bone metabolism of a perimenopausal woman. Typical perimenopausal rates of bone lose are 1-3% per year, which is similar to rates of bone loss in DMPA users, regardless of age of use (1).
- Position Paper. Depot Medroxyprogesterone Acetate and Bone Mineral Density in Adolescents-The Black Box Warning: A Position Paper of the Society for Adolescent Medicine. J Adoles Health 2006; 39: 296-301.