transitive verb. 1  To keep up or carry on; continue: maintain good relations. 2  To keep in an existing state; preserve or retain: maintain one's composure. 3  To keep in a condition of good repair or efficiency: maintain two cars.
Anemia is usually classified based on the size of RBCs, as measured by the mean corpuscular volume (MCV). Anemia can be microcytic (MCV typically less than 80 Î¼m3 [80 fL]), normocytic (80 to 100 Î¼m3 [80 to 100 fL]), or macrocytic (greater than 100 Î¼m3 [100 fL]).
There are three main causes of anemia: blood loss, lower than normal levels of red blood cell (RBC) production, or higher than normal rates of RBC destruction. More than one of these factors can combine to cause anemia. Blood loss is the most common cause of anemia, particularly iron-deficiency anemia. Blood loss can be short term or persist over time. It can be caused by heavy menstrual periods, bleeding in the digestive or urinary tracts, surgery, trauma, or cancer.