Table 4.26. Etiology of the neonatal hyperviscosity syndrome.

Increased intrauterine erythropoiesis:
- Placental insufficiency syndrome - small or large for gestational age, postmaturity (incidence 15 - 17%), toxemia of pregnancy, placenta previa (intrauterine hypoxia).
- Metabolic disorders - congenital adrenal hyperplasia, neonatal thyrotoxicosis.
- Endocrine disorders - maternal diabetes, hypoglycemia, hypocalcemia.
- Chromosomal abnormalities - Down syndrome (trisomy 21), trisomy 13, trisomy 18.
- Drug induced - maternal propranolol therapy.
Placental hypertransfusion (most common cause):
- Management of the umbilical cord - delayed cord clamping, milking cord, holding newborn below level of the placenta while cord is pulsating, administration of oxytocic drugs.
- Twin-to-twin transfusion (polycythemia in one, anemia in other).