The Effect of Depo Medroxyprogesterone Acetate (DMPA) on Cerebral Food Motivation Centers: A Pilot Study using Functional Magnetic Resonance Imaging.

OBJECTIVE: The primary objective is to examine activation of food motivation centers in the brain before and 8 weeks after depo medroxyprogesterone acetate (DMPA) administration.

STUDY DESIGN: This prospective experimental pilot study examined the effects of DMPA on food motivation centers utilizing functional magnetic resonance imaging (fMRI) in eight nonobese, ovulatory subjects. fMRI blood oxygen level dependent (BOLD) signal was measured using a 3-Tesla Scanner while participants viewed images of high-calorie foods, low-calorie foods and nonfood objects. fMRI scans were performed at baseline and 8 weeks after participants received one intramuscular dose of DMPA 150 mg. fMRI data were analyzed using the FMRIB Software Library. Changes in adiposity and circulating leptin and ghrelin levels were also measured.

RESULTS: There was a greater BOLD signal response to food cues in brain regions associated with food motivation (anterior cingulate gyrus, orbitofrontal cortex) 8 weeks after DMPA administration compared to baseline (z>2.3, p<.05 whole-brain analysis clustered corrected). No statistically significant change was detected in circulating leptin or ghrelin levels or fat mass 8 weeks after DMPA administration.

CONCLUSION: Analysis of differences in food motivation may guide the development of interventions to prevent weight gain in DMPA users.

IMPLICATIONS: These data support a neural origin as one of the mechanisms underlying weight gain in DMPA users and may guide future research examining weight gain and contraception.