Newborn heart and normal circulation
Illustration above shows normal circulation through heart and lungs after the baby is born.

What is persistent pulmonary hypertension in the neonate (PPHN)?

PPHN refers to a serious breathing problem in newborns. It usually happens in full-term babies or babies who were born at 34 weeks or more. These babies often have other types of breathing conditions.

This condition may also be known as persistent pulmonary hypertension in the newborn and/or persistent fetal circulation syndrome.

How does persistent pulmonary hypertension in the neonate (PPHN) occur?

During pregnancy, the baby gets its oxygen from its mother and the placenta. Very little blood goes to the lungs because the blood vessels in the baby’s lungs are mostly closed. The blood vessels only open after birth when the baby takes his or her first breaths. The vessels then allow blood to travel to the lungs to get oxygen. PPHN happens when the blood vessels do not open up enough, which means that there is a limit on how much oxygen is sent to the brain and organs. This is why PPHN is so dangerous.

What are the risk factors for persistent pulmonary hypertension in the neonate (PPHN) ?

Although the cause is unknown, certain factors increase the infant’s risk of developing PPHN. These factors include:

  • Meconium aspiration: This happens when the baby breathes in its own sticky poop (meconium).
  • Infection.
  • Respiratory distress syndrome (RDS): This breathing difficulty happens in infants who do not have fully developed lungs.
  • Lack of oxygen before or during birth.
  • Diaphragmatic hernia: This refers to a hole in the diaphragm, which is the muscle that keeps the chest separate from the abdomen. A hernia is when organs from one side push through the hole--in this case, organs from the abdomen intrude on the chest.

What causes persistent pulmonary hypertension in the neonate (PPHN)?

The cause of PPHN is not known.

In PPHN, failure of lung vessels to open enough can cause “back-pressure” and force the heart to keep using “fetal” (pre-birth) circulation pathways. These shortcuts (illustration above) ― the ductus arteriosus (DA) and the foramen ovale (FO) ― allow low-oxygen blood to mix in with blood pumped to the rest of the baby’s body.

What are symptoms of persistent pulmonary hypertension in the neonate (PPHN)?

Symptoms of PPHN include:

  • Breathing problems such as rapid or slow breathing, grunting, and retracting.
  • Blue color to the skin.
  • Hands and feet that are cool to the touch.
  • Low blood pressure throughout the body.
  • Low blood oxygen levels.

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