It occurs in 1–2 infants per 1000 live births. It is more common in males and in areas with higher altitudes. Additionally, two percent of infants with respiratory distress syndrome develop PPHN.
Persistent fetal circulation
Alveolar capillary dysplasia
Neonatal sepsis
Foetal cerebral redistribution
Umbilical cord compression
Shaken baby syndrome
Fetal distress
Placental insufficiency