Decreased tissue inhibitor of metalloproteinase in the endometrium of women using depot medroxyprogesterone acetate: a role for altered endometrial matrix metalloproteinase/tissue inhibitor of metalloproteinase balance in the pathogenesis of abnormal uterine bleeding?

Abnormal uterine bleeding is commonly associated with progestin-only contraceptives, including depot medroxyprogesterone acetate (DMPA), and remains the main reason why these agents are discontinued. Matrix metalloproteinases (MMP), enzymes which degrade specific extracellular matrix components, and leukocytes are implicated in menstruation. Alteration in endometrial MMP-9 and leukocytes has been described in users of other progestin-only contraceptives, suggesting a potential role in the pathogenesis of abnormal uterine bleeding.