Deficiency of red cells, or hemoglobin, in the blood.

Anemia is a medical condition in which the quantity of red blood cells falls below an acceptable level. Red blood cells, produced in the bone marrow, contain hemoglobin, the component of blood that carries oxygen from the lungs to the body's tissues. Red blood cells circulate in the blood for about 120 days and are then filtered out by the lymphatic system and destroyed, usually in the spleen. When more cells are destroyed than are produced, anemia can result.

Anemia can range from mild to life-threatening in severity, and has a number of causes. The disease can be caused by a single significant blood loss or from a long-term chronic illness. Fetal anemia can develop when the mother's and fetus's blood have Rh factor incompatibility. During prenatal tests and newborn examinations, the mother and infant are routinely tested for anemia...