Causes
The causes of anemia may be classified as impaired red blood cell (RBC) production, increased RBC destruction (hemolytic anemia), blood loss and fluid overload (hypervolemia). Several of these may interplay to cause anemia. The most common cause of anemia is blood loss, but this usually does not cause any lasting symptoms unless a relatively impaired RBC production develops, in turn, most commonly by iron deficiency. Impaired production
Disturbance of proliferation and differentiation of stem cells
Pure red cell aplasia
Aplastic anemia affects all kinds of blood cells. Fanconi anemia is a hereditary disorder or defect featuring aplastic anemia and various other abnormalities. Anemia of kidney failure due to insufficient production of the hormone erythropoietin
Anemia of endocrine disease
Disturbance of proliferation and maturation of erythroblasts
Pernicious anemia is a form of megaloblastic anemia due to vitamin B12 deficiency dependent on impaired absorption of vitamin B12. Lack of dietary B12 causes non-pernicious megaloblastic anemia. Anemia of folate deficiency, as with vitamin B12, causes megaloblastic anemia
Anemia of prematurity, by diminished erythropoietin response to declining hematocrit levels, combined with blood loss from laboratory testing, generally occurs in premature infants at two to six weeks of age. Iron deficiency anemia, resulting in deficient heme synthesis
Thalassemias, causing deficient globin synthesis
Congenital dyserythropoietic anemias, causing ineffective erythropoiesis
Anemia of kidney failure (also causing stem cell dysfunction)
Other mechanisms of impaired RBC production
Myelophthisic anemia or myelophthisis is a severe type of anemia resulting from the replacement of bone marrow by other materials, such as malignant tumors, fibrosis, or granulomas.
Maceration  may refer to:

Maceration (food), in food preparation
Maceration (wine), a step in wine-making
Carbonic maceration, a wine-making technique
Maceration (sewage), in sewage treatment
Maceration (bone), a method of preparing bones
Acid maceration, the use of an acid to extract micro-fossils from rock
Maceration, in chemistry, the preparation of an extract by solvent extraction
Maceration, in biology, the mechanical breakdown of ingested food into chyme
Skin maceration, in dermatology, the softening and whitening of skin that is kept constantly wet
Maceration, in poultry farming, a method of chick culling