Table 1: Etiology of neonatal polycythemia [22].

Erythrocyte transfusion (Passive)
Delayed clamping of umbilical cord
Uncontrolled or precipitous delivery
Intrapartum hypoxia
Twin-to-twin transfusion (In 10-15% of monochorionic twins)
Materno-fetal transfusion
Increased intrauterine erythropoesis (Active)
Plasental insufficiency
Other hypertensive disorders
Other vascular problems
Maternal hypoxemia due to cardiac or pulmonary diseases
Cardiac and pulmonary disorder
Drugs (i.e. propranolol)
High altitude
Diseases associated with fetus
Large-for-gestational age newborns
Maternal diabetes mellitus
Beckwith-Wiedemann syndrome
Endocrine disorders (Congenital adrenal hyperplasia, hypothyroidism, hyperthyroidism)
Chromosomal disorders (Trisomi 21, 18, and 13)