Contraceptive Pearl: DMPA and Bone Health
Written by Meghna Nandi, MD
Depot Medroxyprogesterone Acetate (DMPA) is a commonly used, highly efficacious, progestin-only injectable contraceptive method. Many contraceptive users are drawn to DMPA for the privacy it affords and the convenience of its three-month (11-15 week) dosing schedule.1 Although DMPA has many advantages, there are concerns over the method’s impact on bone health. DMPA prevents pregnancy by inhibiting gonadotropin release, leading to anovulation. This process also decreases estradiol production, which in turn can decrease bone mineral density (BMD).2,3
Several studies using dual-energy x-ray absorptiometry (DEXA) measurements have demonstrated a dose and duration-dependent decrease in BMD among DMPA users. Longitudinal studies have reported decreases in BMD that increase with number of years used, ranging from 5.7-7.5% after 2 years.2 Some data also suggest bone loss is greater in adolescents and young adults.3 Although there is a demonstrated association between DMPA use and decreased BMD, these losses in BMD have been found to be mostly, if not completely, reversible once DMPA is stopped.2,3 One Cochrane review in 2014 including multiple randomized controlled trials found that while DMPA was associated with decreased BMD, there was insufficient evidence to determine its effect on fracture risk.4 Another Cochrane review in 2015 looking at only observational data found that DMPA users had an increased risk of fractures based on moderate quality evidence from two observational studies. Fracture risk, like BMD decrease, was greater with longer DMPA use, with 17-44% increase with any use, and 30%-116% increase with longer duration of use (>10 prescriptions, >4 years, >10 years).5
Taken together, the literature supports the overall safety of DMPA. No professional organizations restrict DMPA use for less than two years. However, based on initial data on DMPA and BMD, the Food and Drug Administration (FDA) issued a “Black Box” warning in 2004, cautioning against the use of DMPA for more than two years. The “Black Box” warning also states that future fracture risk in adolescent users is unknown and that BMD loss may not be completely reversible, based on limited data from a small sample size finding incomplete recovery of bone density at the hip after five years of DMPA discontinuation in participants who had used DMPA for two or more years.2,6
On the other hand, the World Health Organization, Centers for Disease Control and Prevention (CDC), and American College of Obstetricians and Gynecologists (ACOG) all advise that the effect of DMPA on BMD and fracture risk should not prevent DMPA use beyond two years and that even in adolescent patients and perimenopausal patients, who are at greater risk of BMD loss and fracture, advantages of DMPA use likely outweigh risks in the absence of other major risk factors for BMD loss.2,7,8 The CDC Medical Eligibility Criteria for Contraceptive Use highlights taking into account DMPA’s impact on bone health in patients with chronic conditions that also impact bone health, such as multiple sclerosis and chronic kidney disease.8 Furthermore, there are no recommendations for monitoring BMD with DEXA while using DMPA.
As with all forms of contraception, person-centered counseling is paramount when discussing DMPA with patients. As providers, we should counsel patients about the FDA Black Box warning, discuss what current evidence tells us about the impact of DMPA on bone health, review why concerns about DMPA on BMD and fracture risk do not preclude DMPA use beyond two years, and consider other factors that may influence bone health in patients interested in DMPA, including age and comorbidities.2
RHAP Resources:
Your Birth Control Choices Fact Sheet
The Shot (Depo Provera) User Guide
The Home Shot / Depo-Provera Sub-Q User Guide
Sources:
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