Previous studies had shown that women who use DMPA, marketed under the brand name Depo-Provera, experience a loss of bone mineral density during the time they are using the contraceptive. Because women are developing a large amount of their bone mass from ages 15 to 19, researchers were concerned that DMPA use might place adolescents at higher risk for bone fracture or osteoporosis later in life.
"This study shows that after adolescents stop using DMPA, their bone density can increase to levels comparable to those of other women in their age group," said Duane Alexander, M.D., Director of the NICHD.
The study authors wrote that 10 percent of female U.S. female adolescents from 15 to 19 who are using birth control use DMPA, as compared to 3 percent of U.S. women overall.
Researchers believe that DMPA interferes with bone mineral density by lowering levels of estrogen, a hormone that promotes bone mineral density in women.
The findings appear in the February Archives of Pediatrics and Adolescent Medicine. The study was conducted by Delia Scholes, Ph.D., of the Group Health Cooperative in Seattle, Washington, and her colleagues.
To conduct the study, the researchers measured hip, spine, and whole body bone mineral densities in 170 healthy female adolescents ages 14 to 18. Of these, 80 had used DMPA, and 90 had not. Some of the 90 who had not used DMPA had used other forms of contraception, including oral contraceptives. Oral contraceptives also contain hormones. Some contain a combination of the hormones estrogen and progestin, some contain only progestin. It is not known whether oral contraceptive use affects bone mineral density and NICHD
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Contact: Bob Bock or Marianne Glass Miller
bockr@mail.nih.gov
301-496-5133
NIH/National Institute of Child Health and Human Development
7-Feb-2005