Polycythemia can occur when there are too many red blood cells in an infant's blood.
The percentage of red blood cells (RBCs) in the infant's blood is called the "hematocrit." When this test is greater than 65%, polycythemia is present.
Polycythemia can result from conditions that develop before birth. These may include:
- Delay in clamping the umbilical cord
- Diabetes in the baby's birth mother
- Inherited diseases and genetic problems
- Too little oxygen reaching body tissues (hypoxia)
- Twin-twin transfusion syndrome (This occurs when blood moves from one twin to the other.)
The extra RBCs can slow or block the flow of blood in the smallest blood vessels. This is called hyperviscosity. This may lead to tissue death from lack of oxygen. This blocked blood flow can affect all organs, including the kidneys, lungs, and brain.
Symptoms may include:
- Extreme sleepiness
- Feeding problems
Exams and Tests
There may be signs of breathing problems, kidney failure, low blood sugar, or newborn jaundice.
If the baby has symptoms of hyperviscosity, a blood test to count the number of red blood cells will be done. This test is called a hematocrit.
Other tests may include:
- Blood gases to check oxygen level in the blood
- Blood sugar (glucose) to check for low blood sugar
- Blood urea nitrogen (BUN), a substance that forms when protein breaks down
The baby will be monitored for complications of hyperviscosity. Intravenous (IV) fluid may be given. A partial volume exchange transfusion is sometimes still done in some cases. However, there is little evidence that this is effective.
The outlook is good for infants with mild hyperviscosity. Good results are also possible in infants who receive treatment for severe hyperviscosity. The outlook will depend largely on the reason for the condition.
Some children may have mild developmental changes. Parents should contact their health care provider if they think their child shows signs of delayed development.
Complications may include:
- Death of intestinal tissue (necrotizing enterocolitis)
- Decreased fine motor control
- Kidney failure
Neonatal polycythemia; Hyperviscosity - newborn
Diab Y, Luchtman-Jones L. Hematologic and oncologic problems in the fetus and neonate. In: Martin RJ, Fanaroff AA, Walsh MC, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 10th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 88.
Maheshwari A, Carlo WA. Blood disorders. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2016:chap 103.
Review Date 5/14/2017
Updated by: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.