A person with a low MCV has microcytic anemia, explains MedlinePlus. A low MCH indicates hypochromic anemia. Iron deficiency is a common cause of both microcytic and hypochromic anemia. Iron deficiency might be caused by blood loss from menstrual bleeding, cancer or ulcers; the body's inability to absorb iron; a lack of iron in the diet; or the body's increased need for iron due to pregnancy, states MedlinePlus.