A study of the mechanism of weight gain in medroxyprogesterone acetate users.

Twelve non-lactating Thai women using the injectable contraceptive medroxyprogesterone acetate (DMPA) were studied in order to elucidate the mechanism of weight gain frequently seen among DMPA users. The study design included repeated estimations of body fluid compartments (total, extracellular and intravascular) and of nitrogen metabolism, as well as anthropometric measurements. The mean weight remained constant in this group of women after one year of treatment. But 25% of them demonstrated a mean weight gain of 6.05 kilograms, while another 25% showed a mean weight loss of 3.50 kilograms. None of the subjects (including those who gained and lost weight) showed significant changes in her fluid compartmental size, creatinine excretion rate, or nitrogen metabolism. However, skin-fold thicknesses were positively correlated to body weight changes. It can be concluded that medroxyprogesterone acetate when used as injectable contraceptive does not appear to have significant anabolic or fluid retaining properties, and that weight gain appears to be associated mainly with fat deposition.