Congenital Diaphragmatic Hernia (CDH)

The diaphragm is a muscle underneath both sides of the lungs that develops in the first trimester of pregnancy.  It is a critical component of the respiratory system and helps to separate the organs of the chest (heart and lungs) from the organs of the abdomen (liver, stomach, spleen and intestines). In a congenital diaphragmatic hernia (CDH), the diaphragm does not completely form leaving a hole between the chest and the abdomen.   Depending on how large the hole is, the intestines, spleen, liver and stomach may move up into the chest cavity where they will take up space from the developing lungs. As a result, the lungs develop poorly leaving the baby with a smaller number of air sacs, blood vessels and airways. When this happens, breathing can be difficult or impossible after the baby is born.   
It is estimated that one in every 4,000 births is affected by a CDH. Ninety percent of the time, the CDH forms on the left side of the diaphragm. CDH usually occurs as an isolated problem but can be associated with congenital diseases of the heart, lung, airway, kidney and intestine. 

What Causes CDH?

The cause of fetal diaphragmatic hernia is largely unknown and usually occurs without any additional abnormalities.  Occasionally, CDH is associated with genetic and non-genetic syndromes and genetic testing is typically recommended in all cases. The overall value of genetic testing may be discussed with your physician or a genetic counselor. The risk of a CDH occurring again in a future pregnancy is extremely low (1 to 2%).    

How is CDH Diagnosed?

The majority of cases of CDH are discovered during an anatomy ultrasound done by obstetricians as part of routine prenatal care.  The ultrasound may show the stomach, intestines or liver in the baby’s chest next to the lungs. The location of the opening in the diaphragm affects which abdominal organs move up (or herniate) into the baby’s chest. In a left-sided CDH — which is most common — the stomach, intestines and sometimes the liver can herniate into the baby’s chest. In a right-sided CDH, the liver always moves into the chest with the intestines but the stomach typically remains within the abdomen.  The heart is typically pushed to the opposite side by the extra organs in the chest.

When a CDH is diagnosed during pregnancy, a specialized CDH fetal ultrasound, fetal echocardiogram and a fetal MRI are recommended. These tests provide a comprehensive assessment of the CDH severity and the permit detection of other abnormalities that may exist. To properly monitor the baby’s growth and development, the imaging tests should be repeated later in the pregnancy.

How is the Severity of CDH Determined?

Simple observations like the position of the fetal liver and stomach taken from a routine ultrasound provides the earliest assessment of the CDH severity. As the liver and stomach progressively herniate into the fetal chest, the fetal lungs will be smaller than normal which is a condition known as lung hypoplasia. Additionally, the blood vessels within the lungs may also develop poorly leading to high blood pressure in the lungs; a condition known as pulmonary hypertension. With less herniation, the fetus usually has a less severe form of CDH and therefore a better prognosis.

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Experienced fetal centers can perform a specialized CDH ultrasound and fetal MRI examination to provide a more detailed assessment of the impact of the CDH on fetal lung development. The ultrasound measurement of the observed-to-expected lung-to-head ratio (o/e LHR) and the MRI measurement of the observed-to-expected total lung volume (o/e TLV) compare the lung development in cases of CDH to the lung development in normal fetuses at the same gestational age. In experienced hands, these tests facilitate measurement of the fetal lung volume and determine if a fetus fits into the mild, moderate or severe risk disease category. This assessment allows the CDH care team to plan the best care strategy for the pregnancy and the care after birth as patients in each of these categories have similar risks and outcomes.

At Lurie Children’s and Prentice Women’s Hospital, the Multidisciplinary CDH Team uses care protocols based on the latest scientific evidence. These care protocols have been optimized through the clinical experience of caring for several hundred mothers and babies with a prenatal diagnosis of CDH and result in the best possible outcomes.

Management of the CDH Pregnancy

Once diagnosis of a CDH is suspected, a comprehensive consultation with the Multidisciplinary CDH Team is recommended along with a specialized fetal CDH ultrasound, fetal echocardiogram and fetal MRI performed during this visit. The Multidisciplinary CDH team is comprised of specialists with extensive experience in the comprehensive care of CDH including Fetal and Pediatric Surgeons, Maternal Fetal Medicine specialists, Neonatologists, Fetal Cardiologists, Fetal Radiologists, Obstetrical and Neonatal Nurses, Genetic Counselors, Social Workers, Nutritionists and Clinical Research Managers.

At the first consultation visit, the CDH team will get to know you and your family and review all of the prenatal testing with you. Our goal is to work with you to determine a personalized treatment plan that supports anticipated needs of the pregnancy and the care plan after birth. Most cases of CDH will only require some additional monitoring during the pregnancy and a coordinated delivery at a hospital capable of providing all aspects of CDH care for the mother and baby. However, with increasing CDH severity, specialized care during pregnancy may be an option. In the most severe forms of CDH, a surgical intervention called Fetoscopic Endoluminal Tracheal Occlusion (FETO) may be recommended to improve the baby’s outcome. FETO is an innovative treatment option that helps the baby’s lungs to develop as much as possible before birth. Because the treatment carries additional risks, specific inclusion and exclusion criteria exist and extensive counseling with the surgical team is needed to ensure a balance of risk and safety for the mother and the fetus.

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A second consultation visit often occurs later in the 3rd trimester of the pregnancy to plan for delivery management needs. Here, some of the prenatal testing is repeated and provides the best information regarding the CDH severity and the anticipated needs of the remaining pregnancy, delivery and care after birth. The delivery management depends on several factors, including the severity of the CDH and obstetrical needs for the mother. A term vaginal delivery is typically recommended unless obstetrical needs suggest that an alternative approach would be beneficial to the mother or the baby.

Care of the CDH Baby after Delivery

he Multidisciplinary CDH Team will determine the best approach and attend the delivery for the CDH baby.  At the delivery, a newborn with CDH is typically unable to breathe on their own because of poor lung development. Most babies need help from a breathing machine called a ventilator, as well as assistance with feeding to grow and develop.  All of the babies are admitted to the Lurie Children’s Neonatal Intensive Care unit (NICU) for the entirety of the care. Here, the Multidisciplinary CDH Team will continue to care for them through daily collaborative rounds.

The first phase of the baby’s NICU care is the resuscitation and stabilization phase which begins at delivery and continues for approximately 3 – 5 days.  During that time, a CDH newborn will experience changes in the circulation of blood through the heart and lungs similar to other newborns.  However, a baby with CDH can have significant trouble maintaining oxygen levels and clearing carbon dioxide due to lung hypoplasia and pulmonary hypertension. For this reason, the surgery to repair the CDH is typically not performed until after the newborn has stabilized and can better tolerate an operation. If the newborn cannot be stabilized while on the ventilator, ECMO (extracorporeal membrane oxygenation) may be required for some time. This machine helps to pump blood and bring oxygen to the rest of the baby’s body. For infants with severe breathing problems, ECMO provides critical time for growth, development and repair of the CDH with stable oxygenation and blood pressure.

The second phase of NICU care is the surgical phase which begins no earlier than 3 days after birth but may be delayed for several days if the baby remains unstable. In cases of a small defect, the CDH repair is done by closing the hole with stitches. These surgeries are performed through an abdominal incision just below the ribs (open CDH surgery) or through 3 very small incisions in the baby’s chest (minimally invasive thoracoscopic CDH surgery) thus avoiding a large incision. With larger defects, the surgeons will make an open abdominal incision and use a transversus abdominis (TrA) muscle flap from the inner layer of the baby’s abdominal wall musculature to close the hole. The TrA flap is superior to mesh alternatives because it is comprised of the baby’s own tissues and will grow like the other muscles in the body. Sometimes, there is not enough room in the abdomen to accommodate the organs that developed in the chest. In these situations, the baby will require a temporary abdominal wall silo to allow time for the growth of the abdomen.

The final phase of the NICU care for CDH babies is the feeding and growing phase. After the baby recovers from the repair of the CDH, the goal for the remainder of the NICU care is for the baby to breathe and eat independently. Weaning from the ventilator and breast milk or formula feeding via a nasogastric tube typically begins 1-2 weeks after surgery. Most often, the baby will learn to breathe and eat normally as they grow. For most CDH babies, this happens slowly over a period of several weeks to months. The CDH dieticians, dpeech therapists, lactation specialists and NICU nursing will work closely with the mother to harmonize nutrition, growth, development, and bonding in the baby’s quiet and private NICU room. The ultimate goal is to prepare the baby and family to safely transition to their home. The amount of time the infant will stay in the NICU depends on their progress with breathing, feeding and growing. Adequate nutrition and growth are essential to develop strong lungs, muscles, brain, immune system and other organ systems that will allow the baby to survive and thrive.

What Are the Long-Term Outcomes for Babies with CDH?

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CDH: What It Looks Like and Care Options -  From FETO Surgery and Postnatal Surgical Repair to Follow-Up Care

The Chicago Institute for Fetal Health and Lurie Children’s are leaders in the care of CDH with the highest survival rates and lowest ECMO rates in the world (CIFH Volumes and Outcomes). Here again, adequate nutrition and growth are essential. The vast majority of CDH babies survive and grow up to have normal, active and independent lives. Lung growth continues for the first decade of life allowing for normal lung development to occur even when severe lung hypoplasia was present at birth. Care by the Multidisciplinary CDH Team will continue after discharge from the NICU in partnership with the baby’s primary pediatrician to monitor and support the baby’s needs. Some babies have long-term medical problems and need more frequent follow-up care after they return home. These problems may include chronic lung disease, pulmonary hypertension, nutritional problems such as gastroesophageal reflux disease (GERD), neurodevelopmental delays, high-frequency hearing loss and orthopedic deformities. Many of these problems can be treated with medications and therapy — allowing the child to have a better quality of life. Finally, maintaining periodic follow-up with the Multidisciplinary CDH Team ensures that your child will have all of the support needed to lead a healthy and active life.