The primary objective of this study is to assess the safety of an investigational intravenous iron (ferric carboxymaltose [FCM]) or an equal dose of iron dextran and explore the mechanism of hypophosphatemia following administration of FCM or that of an equal dose of iron dextran when treating women with iron deficiency anemia due to heavy uterine bleeding (HUB).

To assess the safety of an investigational intravenous iron (ferric carboxymaltose [FCM]) or an equal dose of iron dextran and explore the mechanism of hypophosphatemia following administration of FCM or that of an equal dose of iron dextran when treating women with iron deficiency anemia due to heavy uterine bleeding (HUB).

Inclusion Criteria:

• Female subjects > or = to 18 years of age
• History of Heavy Uterine Bleeding within the past 6 months
• Screening visit central laboratory Hgb < 12 g/dL
• Screening Visit ferritin < or = to 100 ng/mL or < or = to 300 when transferrin saturation (TSAT) is < or = to 30%
• Demonstrate the ability to understand the requirements of the study, willingness to abide by study restrictions and to return for the required assessments

Exclusion Criteria:

• Known hypersensitivity reaction to any component of ferric carboxymaltose or iron dextran
• Previously randomized in a clinical study of ferric carboxymaltose
• Requires dialysis for treatment of chronic kidney disease
• Chronic kidney disease, marked by estimated glomerular filtration rate < 60 ml/min/1.73m squared
• Previous kidney transplant
• History of primary hypophosphatemic disorder
• Hypophosphatemia < 2.6 mg/dl
• No evidence of iron deficiency
• During the 10 day period prior to screening has been treated with intravenous iron
• During the 30 day period prior to screening or during the study period has or will be treated with erythropoiesis stimulating agents (ESA) in a regimen that is off label
• During the 30 day period prior to screening or during the study period has or will be treated with a red blood cell transfusion, radiotherapy and/or chemotherapy
• During the 30 day period prior to screening or during the study period has or will require a surgical procedure that necessitates general anesthesia
• Any non-viral infection
• Aspartate aminotransferase (AST) or Alanine Aminotransferase (ALT) at screening, as determined by central labs, greater than 1.5 times the upper limit of normal
• Known positive hepatitis with evidence of active disease
• Received an investigational drug within 30 days of screening
• Alcohol or drug abuse within the past 6 months
• Hemochromatosis or other iron storage disorders
• Malignancy history within the past 5 years other than basal or squamous cell skin cancer
• Any other laboratory abnormality, medical condition or psychiatric disorders which in the opinion of the investigator would put the subject's disease management at risk or may result in the subject being unable to comply with study requirements
• Pregnant or sexually-active female subjects who are of childbearing potential and who are not willing to use an acceptable form of contraception
• Untreated primary hyperparathyroidism
• Untreated gastrointestinal malabsorption (e.g., sprue)

8 months