This study investigates whether intravenous (IV) iron \[Feraheme (ferumoxytol) injection)\] is a better treatment than oral iron pills (ferrous sulfate) for correcting anemia in women who have heavy menstrual bleeding and anemia. Investigators will study whether women's blood counts respond better, respond more quickly, and if women prefer the IV treatment or the oral treatment. Women who have heavy menstrual bleeding and anemia will be randomly assigned to receive treatment with either oral iron pills or IV iron infusions. Investigators will then check whether and how quickly the anemia improves, and survey participants on how satisfied they were with the treatment.