juxtaposition (plural juxtapositions) 1  The nearness of objects with little or no delimiter. 2  The extra emphasis given to a comparison when the contrasted objects are close together.
Hemolytic disease of the newborn (HDN), also known as alloimmune HDN or erythroblastosis fetalis, is a potentially fatal alloimmune condition where fetal red blood cells are destroyed by transplacentally acquired maternal antibodies. RhD is the most common offending paternal antigen.
When the disease is moderate or severe, many erythroblasts (immature red blood cells) are present in the fetal blood, and so these forms of the disease can be called erythroblastosis fetalis (or erythroblastosis foetalis).mong these antibodies are some which attack the red blood cells in the fetus' circulation, which are broken down and destroyed (hemolysis). The fetus can develop reticulocytosis and anemia. This fetal disease ranges from mild to very severe, and fetal death from heart failure (hydrops fetalis) can occur.