Definition of Hyperviscosity - newborn:

Hyperviscosity of the newborn is the slowing and blockage of blood flow that results when there are too many red blood cells in an infant's blood.

Causes, incidence, and risk factors:

Hyperviscosity can occur when the percentage of red blood cells (RBCs) in the infant's blood,, called the "hematocrit," is greater than 65%. This may result from various conditions that develop before birth, such as:

• Birth defects
• Delay in clamping the umbilical cord
• Diabetes in the baby's birth mother
• Inherited diseases
• Not enough oxygen reaching body tissues (hypoxia)
• Twin-twin transfusion syndrome, which occurs when blood moves from one twin to the other.

The extra RBCs can block the flow of blood in the smallest blood vessels. This may lead to tissue death from lack of oxygen. This blocked blood flow can affect all organs, including the kidneys, lungs, and brain.