Newborn Polycythemia Overview
Learn About Newborn Polycythemia
Polycythemia means there are too many red blood cells (RBCs) in an infant's blood.
Neonatal polycythemia; Hyperviscosity - newborn
The percentage of RBCs in the infant's blood is called the "hematocrit." When this 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), such as from congenital heart or vascular (blood vessel) abnormalities
- Twin-twin transfusion syndrome (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
- Seizures
The baby will be monitored for complications of hyperviscosity. Fluids may be given through the vein. A partial volume exchange transfusion is sometimes still done in some cases. However, there is little evidence that this is effective. It is most important to treat the underlying cause of the polycythemia.
Lisanne Tollenaar practices in Leiden, Netherlands. Ms. Tollenaar is rated as an Elite expert by MediFind in the treatment of Newborn Polycythemia. Her top areas of expertise are Newborn Polycythemia, Twin-To-Twin Transfusion Syndrome, Anemia, and Intrauterine Growth Restriction.
Enrico Lopriore practices in Leiden, Netherlands. Mr. Lopriore is rated as an Elite expert by MediFind in the treatment of Newborn Polycythemia. His top areas of expertise are Twin-To-Twin Transfusion Syndrome, Fetal and Neonatal Alloimmune Thrombocytopenia, Anemia, Newborn Polycythemia, and Endoscopy.
Sophie Groene practices in Leiden, Netherlands. Ms. Groene is rated as an Elite expert by MediFind in the treatment of Newborn Polycythemia. Her top areas of expertise are Newborn Polycythemia, Intrauterine Growth Restriction, Twin-To-Twin Transfusion Syndrome, and Anemia.
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
- Seizures
- Stroke
Published Date: April 06, 2025
Published By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
Owusu-Ansah A, Letterio J, Ahuja SP. Red blood cell disorders in the fetus and neonate. In: Martin RJ, Fanaroff AA, eds. Fanaroff and Martin's Neonatal-Perinatal Medicine. 12th ed. Philadelphia, PA: Elsevier; 2025:chap 81.
Tashi T, Prchal JT. Primary and secondary erythrocytosis. In: Fish JD, Lipton JM, Lanzkowsky P, eds. Lanzkowsky's Manual of Pediatric Hematology and Oncology. 7th ed. Cambridge, MA: Elsevier Academic Press; 2022:chap 10.
Thom CS, Lambert MP. Blood disorders. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 138.