SAN FRANCISCO — The bone loss associated with injectable depot medroxyprogesterone acetate can be partially recovered within a few years of the patient's discontinuation, Andrew M. Kaunitz, M.D., reported at the annual meeting of the American College of Obstetricians and Gynecologists.
Moreover, the use of this agent does not warrant regular bone scans for patients receiving it, said Dr. Kaunitz, professor of obstetrics and gynecology at the University of Florida Health Sciences Center in Jacksonville.
“I am hearing that many clinicians are ordering bone mineral density studies on DMPA users, and this is analogous to ordering BMD studies in women because they are breast-feeding,” said Dr. Kaunitz, who presented the study (funded by Pfizer Inc.) at the meeting.
“We don't know how to interpret DEXA [dual-energy x-ray absorptiometry] scans in young women, and we should not be ordering them, whether they are using DMPA or not,” he said.
Concerns about bone loss and use of DMPA (Depo-Provera) peaked last November when the Food and Drug Administration (FDA) added a black box warning to DMPA, advising that “prolonged use of the drug may result in significant loss of bone density.”
The warning also stated that “this bone density loss may not be completely reversible after discontinuation of the drug.”
Dr. Kauntiz's study, which was requested by the FDA, included women aged 25–35 years. It followed 41 DMPA users for almost 5 years of treatment plus almost 2 years after discontinuation of treatment and compared their BMD with that of 66 women who were not using hormonal contraception.
Women who had used DMPA for 5 years showed as much as a 5% decrease in the BMD as measured at the spine and hip compared with their pretreatment baseline. In comparison, BMD decreased no more than 0.4% among the women who were not using the agent.
However, there was substantial recovery in BMD, although not to baseline levels, at 1.8 years after discontinuation: BMD was 1.2% less than baseline in DMPA users almost 2 years after discontinuation of use, compared with 0.5% less than baseline in nonusers.
Dr. Kaunitz said a number of studies with longer follow-up have documented complete recovery of BMD after DMPA discontinuation.
“My speculation is that if we had been able to follow BMD for 3 or more years following DMPA discontinuation, it is likely that complete recovery would have been documented,” he said during an interview with FAMILY PRACTICE NEWS.
He compared the hypoestrogenemia associated with use of DMPA to the similar hormonal state during lactation. “Nursing moms also lose BMD—and not the 1%–2% annually that we see with DMPA use, but 4%–5% in the first year of the baby's life,” he said. “After weaning, just as after discontinuation of DMPA, BMD recovers. And we know from many studies that breast-feeding is not a long-term risk factor for osteoporosis or fractures.”
He said he is also concerned that many physicians may be interpreting the FDA's black box warning as an indication that patients should discontinue DMPA after 2 years.
“In my practice, if the patient continues to be a good candidate after 2 years of use, she certainly can and should continue to use this safe, effective method of contraception,” he said.
For the older patient in whom there is concern about use of DMPA continuing straight into menopause, giving no opportunity for BMD to recover, he said estrogen add-back therapy can prevent BMD decline.
“Am I calling for routine add-back therapy? Absolutely not. But could there be a role for it in some select patients? Certainly,” he said.