What is hemolytic disease of the fetus and newborn?

Also known as: erythroblastosis fetalis.

Hemolytic disease of the newborn is a condition that occurs when a mother’s blood type is not compatible with her unborn fetus.

Mothers’ (and all humans) blood is categorized by blood type. Each blood type depends on the presence or absence of specific molecules on the surface of red blood cells (called antigens; Rh, A , B, AB and O and others). Blood also contains specialized proteins (called antibodies) which can destroy a different red blood cell type (Rh positive blood has the Rh antigen but no Rh antibody- Rh negative blood has no Rh antigen or Rh antibody).

If a mother is Rh negative and her fetus is Rh positive, any blood passing from baby to mother will result in the mother's blood producing antibodies to it (incompatible blood types) which will cross the placenta and attack and destroy the baby's red cells.

This process is called hemolysis, and occurs not only with Rh incompatibility, but also with type O mothers and in the presence of other blood types.

Reviewed by: Jack Wolfsdorf, MD, FAAP

This page was last updated on: 1/29/2019 3:21:13 PM

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