Does the addition of estrogen help to minimize bone loss in adolescent DMPA users?
Since the mechanism for BMD loss from DMPA is believed to be due to estrogen deficiency, the question arises whether supplementation of estrogen in certain women on DMPA would improve bone density. One study of adolescents has shown that estrogen supplementation diminishes bone loss while on DMPA.
The double-blind randomized controlled trial was conducted in adolescents (age 12-18) who selected DMPA as their form of contraception (1). One hundred and twenty-three girls were started on DMPA and received injections every 12 weeks. They were then randomized to receive monthly injections of estradiol cypionate (EC) or placebo. The main outcome was BMD at 12 and 24 months. At 24 months, the results (percentage change from baseline BMD) were:
- L-spine: 2.8% in the EC group vs. -1.8% in the placebo group (p<.001).
- Femoral neck: 4.7% in the EC group vs. -5.1% in the placebo group (p<.001).
- These data were adjusted for baseline weight and BMD.
There were similar findings noted in a small study of adult pre-menopausal women (mean age 37) on DMPA randomized to daily oral conjugated estrogens or placebo (2).
Despite this information, it may still be premature to routinely recommend estrogen supplementation for adolescent girls on DMPA for birth control. Larger studies on estrogen supplementation, behavioral interventions, and recovery of bone loss after discontinuation of DMPA in adolescents are needed before a recommendation can be made.
- Cromer BA, Lazebnik R, Rome E, Stager M, Bonny A, Ziegler J, Debanne S. Double-blinded randomized controlled trial of estrogen supplementation in adolescent girls who receive depot medroxyprogesterone acetate for contraception. AJOG 2005; 192: 42-7.
- Cundy T, Ames R, Horne A, Clearwater J, Roverts H, Gamble G, Reid I. A randomized controlled trial of estrogen replacement therapy in long-term users of depot medroxyprogesterone acetate. J Clin Endocrinol and Metab 2003; 88(1): 78-81.