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PPHN Risk Factors & Causes

How does Persistant Pulmonary Hypertension of the Newborn (PPHN) Occur? 

PPHN may result from a problem during delivery or another condition that affects the lungs or oxygen supply to the baby in the womb or during childbirth.

In a developing fetus, blood is circulated through the placenta and umbilical cord. It is through the placenta, not the lungs, that carbon dioxide is removed from the blood and replaced with oxygen. The pulmonary artery then carries the oxygenated blood directly to the fetal heart.

Typically, after the baby is born, he begins to breathe air on his own, and his circulatory system begins to operate independently from the mother. Blood is pumped into the newborn's lungs, where carbon dioxide is exchanged for oxygen before the blood returns to the heart.

In a baby with PPHN, however, this "switch" fails to take place. The baby breathes, but his blood does not reach the lungs for the oxygen-carbon dioxide exchange. The pressure in the lungs increases and the blood's failure to deliver needed oxygen throughout the body places a severe stress on vital organs.

In 2006 a study published in the New England Journal of Medicine found that mothers who took SSRI's (such as Paxil) in the second half of pregnancy were six times more likely to deliver an infant with PPHN than mothers who did not take antidepressants at all-or who discontinued their use in the first half of pregnancy.

In many cases, however, the cause of PPHN is unknown. PPHN occurs in approximately one or two in 1,000 babies, typically in term or near-term deliveries. Symptoms usually appear within 12 hours after birth. Sadly, ten to 20 percent of infants with PPHN do not survive.

Learn about the symptoms of PPHN.

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