A prospective comparison of bone density in adolescent girls receiving depot medroxyprogesterone acetate (Depo-Provera), levonorgestrel (Norplant), or oral contraceptives.

ABSTRACT

PIP: In Ohio, data on 31 postmenarcheal women, 12-21 years old and using hormonal contraception (Norplant = 7, Depo Provera = 15, and oral contraceptives [OCs] = 9) were compared with data on 17 controls of similar age to prospectively examine lumbar bone density in girls before and after 1 and 2 years of hormonal contraceptive use and to compare the results with young women not using hormonal contraceptives. The subjects attended a general adolescent clinic at Children's Hospital in Columbus. There was an insufficient number of OC users at 2 years, so they were not included in second year analyses. Initial height and weight were significantly associated with bone density values (p 0.05). Weight accounted for the most variance both at baseline (p 0.001) and after 1 year of treatment (p 0.01). At baseline and 1 year, bone density values between patient groups were not significantly different. At 2 years, however, Norplant users had higher bone density than Depo- Provera users and controls (1.308 vs. 1.004 and 1.087, respectively; p 0.01). After 1 year, Depo-Provera users experienced a decrease (1.53%) in bone density while Norplant users, OC users, and controls experienced an increase in bone density (2.46%, 1.52%, and 2.85%, respectively). The change in bone density between Depo-Provera users and controls was significant (p 0.02). At 2 years, Depo Provera users experienced a decrease in bone density while Norplant users and controls experienced an increase (-3.12% vs. 9.33% and 9.49%, respectively; p 0.0001). This study is important because 50% of adult bone mass is accrued during adolescence. In fact, bone mass peaks during adolescence. It is not known whether bone loss during Depo Provera use is reversible after treatment discontinuation. These findings show that Depo Provera inhibits skeletal bone mineralization in adolescents, at least temporarily, while Norplant and OCs appear to increase bone density.