Is long-term use of medroxyprogesterone acetate (Depo Provera) safe in perimenopausal women for whom estrogen-containing contraceptives are contraindicated (e.g., smokers)? At what age would you recommend a dual energy x-ray absorptiometry (DEXA) scan for these patients?
—NICOLE McHUGH, MSN, CRNP, Narberth, Pa.

While depot medroxyprogesterone acetate (DMPA) provides highly reliable birth control and can alleviate the abnormal uterine bleeding that often accompanies perimenopause, this agent creates a hypoestrogenic hormonal milieu that can adversely impact bone mass. With the FDA’s issuance of a black-box warning in 2004, many providers became increasingly concerned about the impact of DMPA on patients’ bone health. Current evidence implies that this risk may have been overestimated, especially among young women who will be able to regain bone mass before menopause. Most bone loss attributable to DMPA occurs during the first two years of use and is rapidly reversible after discontinuation. In women who may not have time to recover bone mass before menopause, the risks and benefits of DMPA use must be carefully considered. Women with other risk factors for osteoporosis (e.g., strong family history of osteoporosis or fragility fractures; current or past use of glucocorticoids, tobacco, or alcohol; eating disorder; or history of nontraumatic bone fracture) should be counseled against DMPA use.

No firm clinical recommendations exist for bone density testing among premenopausal women; for DMPA users younger than age 45 years, the American College of Obstetricians and Gynecologists does not generally recommend DEXA scanning. Beyond that age, bone mineral density (BMD) testing via DEXA is probably advisable after two to four years’ use of DMPA or sooner if other risk factors for osteoporosis are present. While BMD can be a useful piece of data, fracture risk is more clinically relevant, and BMD must be considered in the context of other risk factors and lifestyle factors. Small studies indicate that women entering menopause while on DMPA have no statistically greater fracture risk than women not using DMPA.

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DMPA should be discontinued if fracture risk is high. Other contraceptives that contain progestin only, such as Implanon and the Mirena intrauterine system, and progestin-only birth control pills, can be used by women in whom estrogen is contraindicated and provide similar benefits to DMPA without compromising BMD. Nonhormonal contraceptives, such as condoms, the diaphragm, or the copper intrauterine device, may also be good alternatives. In low-risk users with normal BMD, consider repeating the DEXA in two years unless other risk factors develop. For all women using DMPA, bone health should be optimized through calcium and vitamin D supplementation, weight-bearing exercise, and the avoidance of tobacco and alcohol. Additional information is available in Goldberg AB, Grimes DA. Injectable contraceptives. In: Hatcher RA, Trussell J, Nelson AL, et al, eds. Contraceptive Technology. 19th ed. New York, N.Y.: Ardent Media, Inc; 2007:157-180.
—Lisa Stern, APRN