The failure of the circulatory system of the newborn to adapt to these changes by lowering PVR leads to persistent fetal circulation.

[4] As a result of low oxygen levels, infants with PPHN are at an increased risk of developing complications, such as asphyxia, chronic lung disease, neurodevelopment issues, and death.

[3] This inability of the newborn to adapt to these changes is caused by various processes, such as: To help with diagnosis, the clinician can watch out for predisposing factors, such as: birth asphyxia, meconium aspiration, use of NSAIDs (non steroidal anti-inflammatory drugs) and SSRIs (selective serotonin reuptake inhibitors) by the mother, and early onset sepsis or pneumonia.

[3] A gradient of 10% or more in oxygenation saturation between simultaneous preductal and postductal arterial blood gas values in absence of structural heart disease documents persistent fetal circulation.

[10] Since this may be a sign of other conditions, persistent fetal circulation must also be characterized by enlargement of right and left ventricles often confirmed through a definitive ECG.

[11] Treatment aims to increase the amount of oxygen in the blood and reverse any causes of hypoxia as well as gain adequate perfusion.

[1] In addition to treating the direct effects of this condition, other management strategies are implemented concurrently to stabilize the newborn.These include, but are not limited to nutritional support, reduction of stressful environment, gentle sedation, monitoring/treating acidosis and establishing normal systemic blood pressure.

In low-resource environments, it is recommended to focus on five main bundles of management:[16] It occurs in 1–2 infants per 1000 live births.