Congenital diaphragmatic hernia, or CDH, is a structural birth defect that occurs early in pregnancy. It is characterized by the incomplete formation of the diaphragm, the muscle that separates the chest from the abdomen. This opening allows abdominal organs, such as the stomach, intestines, and liver, to move into the chest cavity. The presence of these organs in the chest restricts the space available for the lungs to grow, which leads to many of the health challenges associated with CDH.
The Underlying Cause and Diagnosis
In most instances, the specific cause of congenital diaphragmatic hernia remains unknown. The condition is considered multifactorial, meaning a combination of genetic and environmental factors may contribute to its development. While it can occur as an isolated defect, approximately 40% of cases are associated with other anomalies. Research has identified links to certain genetic or chromosomal abnormalities, such as trisomy 13 and 18, though for many families, there is no identifiable genetic cause.
CDH is most frequently discovered before birth during routine prenatal ultrasound screenings, with over 60% of cases identified this way. During a second-trimester ultrasound, sonographers may notice abdominal organs within the chest, a shift in the heart’s position, or a small abdominal circumference. A fluid-filled stomach bubble seen in the chest instead of the abdomen is a common indicator.
If not detected prenatally, CDH is diagnosed shortly after birth. Newborns often present with immediate respiratory distress. Apparent signs include rapid, labored breathing, a scaphoid abdomen (an abdomen that appears sunken in), and cyanosis, a bluish discoloration of the skin from a lack of oxygen. These symptoms prompt a chest X-ray, which can confirm the diagnosis.
Prenatal Interventions and Management
Once a prenatal diagnosis of CDH is confirmed, management focuses on close monitoring and planning for the birth. The expecting parent is referred to a tertiary care center with a specialized neonatal intensive care unit (NICU). This ensures a specialized team is ready to provide immediate care upon delivery. This team includes neonatologists, pediatric surgeons, and respiratory therapists.
Throughout the pregnancy, fetal development is tracked with serial ultrasounds and sometimes a fetal MRI. A measurement used to predict the severity is the lung-to-head ratio (LHR), which compares the size of the unaffected lung to the baby’s head circumference. A smaller LHR suggests more severe lung underdevelopment, known as pulmonary hypoplasia, and helps the medical team anticipate the support the newborn will require.
For fetuses with the most severe forms of CDH, an advanced in-utero procedure may be considered. Fetal Endoscopic Tracheal Occlusion (FETO) is a minimally invasive surgery performed during pregnancy. In this procedure, a small balloon is temporarily placed in the fetus’s trachea to block the outflow of lung fluid, encouraging the lungs to expand. The balloon is removed in a second procedure before birth, with the goal of improving lung function to increase the chances of survival.
Postnatal Stabilization and Surgical Repair
The moments immediately following birth are managed with urgency. The primary goal is to stabilize the baby’s breathing and circulation. The newborn is immediately intubated and connected to a mechanical ventilator to deliver oxygen to the underdeveloped lungs. It is important to avoid using a bag and mask for resuscitation, as this can pump air into the stomach and intestines, further compressing the lungs.
Stabilization can take several days or weeks. The medical team works to manage pulmonary hypertension, a common complication where high blood pressure affects the arteries in the lungs. Medications are used to relax the blood vessels, improving blood flow and oxygenation. The infant’s condition is monitored in the NICU until they are stable enough for surgery.
Once the baby’s lung function and blood pressure have stabilized, surgical repair of the diaphragm is scheduled. The operation involves the pediatric surgeon making an incision in the abdomen to guide the herniated organs back into the abdominal cavity. After the organs are correctly positioned, the surgeon closes the hole in the diaphragm. If the hole is large, a synthetic patch may be required to complete the repair.
Recovery and Long-Term Outlook
Following surgery, the infant’s recovery continues in the NICU. They remain on a ventilator while their lungs adapt and strengthen, with the medical team gradually weaning them off respiratory support as their function improves. This postoperative period is focused on managing the transition to independent breathing.
Children born with CDH often face long-term health challenges that require specialized care. Feeding difficulties are common, as the gastrointestinal tract may be underdeveloped or positioned differently. Many infants require a feeding tube for nutrition. Gastroesophageal reflux disease (GERD), where stomach acid flows back into the esophagus, is also frequently encountered.
Due to initial respiratory distress, some children may experience developmental delays. Regular follow-up with a multidisciplinary team, including specialists, is part of long-term management to monitor lung function, growth, and neurological development. With comprehensive care, many children born with CDH overcome their early health hurdles and lead active, full lives.