Vitamin B12 and/or folic acid deficiency can cause an anemia called as megaloblastic anemia. The deficiency of these causes ineffective red cell formation (ineffective erythropoiesis). This leads to increase in the size of the red blood cells, which is shown by the high mean corpuscular volume. Since the cell size is increased, thus the anemia is called megaloblastic (big cell anemia). A supplement of Vitamin B 12 and folic acid corrects it.
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