New research indicates recovery of bone density after teen DMPA use
More research to emerge — continue to advise teens on bone health
New research indicates that lower bone density appears to recover in adolescent females once they stop using the contraceptive injection depot medroxyprogesterone acetate (DMPA, Depo Provera, Pfizer, New York City).1 Ten percent of adolescent females in the United States rely on the birth control method.2
The Food and Drug Administration moved in late 2004 to add a "black box" warning to the labeling for DMPA to highlight that prolonged use may result in the loss of bone mineral density, which raised concerns about its potential impact in teen users.
Providers still will have to weight the benefits of DMPA, such as its contraceptive efficacy with low motivation, compared to the potential risk of long-term minimal loss of bone density, says David Archer, MD, professor of obstetrics and gynecology and director of the Clinical Research Center at the Eastern Virginia Medical Center in Norfolk.
"Obviously at this stage, we need further data to definitively answer all of the questions," he states. "It should be stressed that despite black box warnings, DMPA is effective as a contraceptive, and this should be the primary consideration in prescribing at this time."
Review earlier research
Concerns about DMPA’s potential impact on bone health have been raised since the 1990s, when initial research determined that women using DMPA had bone density values intermediate between those of normal premenopausal and postmenopausal women.3 A subsequent study of some of the original DMPA users who discontinued the method found that bone density tended to increase after the method was stopped.4
Research published in 2004 indicated that women using DMPA for two years recorded a decline in bone mineral density (BMD) of roughly 6%, compared with a loss of 2.6% among women on oral contraceptives.5
DMPA’s revised labeling now states that bone loss in women who use Depo-Provera is greater with increased duration of use and may not be completely reversible. The contraceptive injection should be used as a long-term birth control method (longer than two years) only if other birth control methods are inadequate, the label advises. Women who continue to use Depo-Provera past the two-year mark should have their BMD evaluated, according to the new labeling.
Adolescence is an important time when it comes to bone health: Half of a woman’s bone mass is gained during puberty and the first several years after menarche; peak bone mass is achieved in the early to mid-20s.6
To conduct the newly-reported study, researchers measured hip, spine, and whole body bone mineral densities in 170 healthy female adolescents ages 14-18.1 In this group, 80 had used DMPA, and 90 had not. Some of the 90 teens who had not used the contraceptive injection had used other forms of birth control, including oral contraceptives (OCs). Participants’ bone mineral densities were checked at the beginning of the study and every six months thereafter for the next two to three years. During that time, 61 of the DMPA users stopped using the drug, which allowed the researchers to see how their bone density changed once they discontinued the method.
What did the researchers find?
- DMPA users experienced an average loss of bone density at the hip of 1.81% per year compared with a loss of 0.19% per year among nonusers.
- Looking at spine BMD, DMPA users had a bone loss of 0.97%, while nonusers had an increase in bone density of 1.32%. Researchers note these bone loss rates are similar to that of women who are breast-feeding or going through menopause.
- Women who were new DMPA users lost bone density more rapidly than did longer-term users.
However, when DMPA users stopped using the method, they gained a significant amount of bone density compared to nonusers for the same period. For example:
- The average amount of bone gained in a year for those who stopped using DMPA was 1.34% at the hip, compared to a slight loss of 0.19 for women who were not taking the drug.
- Density at the spine increased 2.86% for women who stopped using DMPA compared to an increase of 1.32% for women who were not using the method.
The current study was conducted to follow up on an earlier study of women ages 18-39.7 In that research, findings indicated that women lost bone density while using DMPA and increased bone mass after discontinuing the contraceptive. However, the younger women in the current study lost bone density and increased bone density more rapidly than did the older women in the previous study.
"I think our results showing bone recovery following discontinuation of Depo-Provera are quite reassuring," says Delia Scholes, PhD, senior investigator at Group Health Cooperative’s Center for Health Studies in Seattle and the study’s lead investigator. "In my mind, this is an important additional part of the story’ for women and providers as they weigh the risks and benefits of this method and try to make an informed decision about its use."
What are you advising?
While it is prudent to offer women an alternative method of contraception after they have used DMPA for two years or more, clinicians, together with their patients, should determine whether DMPA continues to be the best contraceptive option or whether women could switch to another method, says Susan Wysocki, RNC, NP, president and chief executive officer of the Washington, DC-based National Association of Nurse Practitioners in Women’s Health.
Women who choose DMPA at the family planning and teen clinics at Grady Memorial Hospital in Atlanta are counseled that DMPA product labeling does not recommend long-term use (defined as two consecutive years) unless no other method is right for them. Women still may choose to continue to use DMPA for longer terms if they find other methods unacceptable, according to Miriam Zieman, MD, family planning program director and associate professor of obstetrics and gynecology at Emory University in Atlanta.
The 2004 World Health Organization (WHO) committee gave Depo-Provera use in teens a "2" meaning ". . . advantages of using the method generally outweigh the theoretical or proven risks."8 The heightened FDA "black box" warning may be viewed in the same vein as the WHO "3" category, where "use of the method not usually recommended unless other, more appropriate methods are not available or acceptable," observes Robert Hatcher, MD, MPH, professor of obstetrics and gynecology at Emory.
"A Category 3 rating does not mean you cannot provide the method, but that the classification may be overridden if the person cannot find another appropriate method of contraception," he states.
Clinicians should continue to advise all young women to maintain bone health, including information on eating a healthy diet, smoking cessation, limitation of alcohol, and getting regular weight-bearing exercise such as walking, running, and weight lifting, Hatcher advises.
"Just a small percentage of U.S. teens are getting the recommended amount of daily calcium to build bone health," he notes. "The current questions about DMPA use and bone health serve to reinforce the importance of adequate calcium intake for all adolescents."
References
1. Scholes D, LaCroix AZ, Ichikawa LE, et al. Change in bone mineral density among adolescent women using and discontinuing depot medroxyprogesterone acetate contraception. Arch Pediatr Adolesc Med 2005; 159:139-144.
2. Piccinino LJ, Mosher WD. Trends in contraceptive use in the United States: 1982-1995. Fam Plann Perspect 1998; 30:4-10, 46.
3. Cundy T, Evans M, Roberts H, et al. Bone density in women receiving depot medroxyprogesterone acetate for contraception. BMJ 1991; 303:13-16.
4. Cundy T, Cornish J, Evans MC, et al. Recovery of bone density in women who stop using medroxyprogesterone acetate. BMJ 1994; 308:247-248.
5. Berenson AB, Breitkopf CR, Grady JJ, et al. Effects of hormonal contraception on bone mineral density after 24 months of use. Obstet Gynecol 2004; 103:899-906.
6. DMPA and bone density loss: An update. Contraception Report 1999; 10. Accessed at: www.contraceptiononline.org/contrareport/article01.cfm?art=86.
7. Scholes D, LaCroix AZ, Ichikawa LE, et al. Injectable hormone contraception and bone density: Results from a prospective study. Epidemiology 2002; 13:581-587.
8. World Health Organization. "Improving Access to Quality Care in Family Planning." In: Medical Eligibility Criteria for Contraceptive Use. 3rd ed. Geneva: 2003; Summary Tables.
New research indicates that lower bone density appears to recover in adolescent females once they stop using the contraceptive injection depot medroxyprogesterone acetate (DMPA, Depo Provera, Pfizer, New York City).
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