Why is CDH Surgery Delayed? The Role of Stabilization

It is completely natural to want a physical problem—like a hole in the diaphragm—fixed as quickly as possible. However, contemporary medical care for congenital diaphragmatic hernia (CDH) prioritizes stabilizing the baby’s lungs and heart before attempting surgical repair ^[1].

Years ago, CDH was treated as a surgical emergency, but doctors learned that rushing a newborn into the operating room actually lowered their chances of survival. Today, delaying the surgery for days or even weeks is the standard of care, because the immediate danger to the baby is not the hernia itself, but the condition of their fragile lungs and heart ^[2]. Please know that being in the neonatal intensive care unit (NICU) for 2 to 3 weeks without surgery is completely normal and expected.

The Real Danger: Lungs, Not the Hole

When a baby has CDH, the abdominal organs move into the chest during pregnancy, which prevents the lungs from growing normally. This results in pulmonary hypoplasia (underdeveloped lungs) and pulmonary hypertension (dangerously high blood pressure in the blood vessels of the lungs) ^[2].

Persistent pulmonary hypertension is the primary factor that determines a CDH baby’s survival ^[2]. Because the blood vessels in their small lungs are tight and restricted, the heart has to work extremely hard to pump blood through them. Fixing the hole in the diaphragm does not instantly fix the underdeveloped lungs or the high blood pressure inside them.

The Risks of Immediate Surgery

Surgery is a major trauma to the body. If a baby undergoes surgery immediately after birth, the stress of anesthesia, pain, and the operation itself can trigger a severe spike in their pulmonary hypertension ^[3].

During surgery, the baby must be supported by a breathing machine (ventilator). The intense pressure required to keep them breathing during the operation can cause further damage to their fragile, underdeveloped lungs ^[4]. Additionally, the sudden changes in pressure inside the chest when the abdominal organs are pulled down and the hole is closed can cause the baby’s already-stressed heart to fail.

The “Stabilization” Period

Instead of immediate surgery, NICUs now focus on a phase called postnatal stabilization ^[1]. During this critical waiting period, the medical team works to calm the baby’s body and allow them to adapt to life outside the womb.

While you are waiting, the care team is actively working to:

• Protect the lungs: Using “gentle ventilation” strategies to provide enough oxygen without blowing too much pressure into the fragile lungs, avoiding long-term damage ^[5]. This may involve using specialized ventilators (like oscillators). Doctors may also intentionally allow carbon dioxide levels to run higher than normal—a strategy called permissive hypercapnia—so do not panic if blood gas numbers look “abnormal.”
• Rest the heart: Because most CDH occurs on the left side, the left side of the heart is often smaller or weaker ^[6]. Giving the baby time to stabilize allows the heart to improve its function. In severe cases, a baby might be placed on ECMO (Extracorporeal Membrane Oxygenation), a machine that takes over the work of the heart and lungs to let them fully rest. Research shows that waiting to perform surgery until after a baby is successfully weaned off ECMO reduces mortality ^[7].
• Calm the blood vessels: Giving the blood vessels in the lungs time to relax and become less reactive, which lowers the dangerous pulmonary hypertension ^[1]. The team may use specific inhaled gases or IV medications to help these vessels open up.

How Doctors Know It’s Time for Surgery

The medical team monitors the baby closely to decide when their body is strong enough to handle the stress of surgery. Doctors look for specific signs of “surgical readiness,” which include:

• Stable Oxygen Levels: The baby’s oxygen levels remain steady without requiring maximum support from the ventilator ^[8].
• Reduced Medication Needs: The baby requires less heart-supporting medication (inotropes) to keep their blood pumping effectively ^[8].
• Improved Heart Function: Regular ultrasound scans of the heart (echocardiograms) show that the pulmonary hypertension is resolving and the heart is pumping well ^[9].

Waiting for surgery can be one of the most agonizing parts of the CDH journey for parents. However, this delay is a carefully calculated medical strategy designed to protect your baby’s most vital organs and give them the best possible chance of a safe and successful repair.