Congenital Diaphragmatic Hernia

A congenital diaphragmatic hernia (CDH) is a birth defect (congenital disorder) that occurs during fetal development. It means that a fetus’s diaphragm isn’t fully formed or strong enough to be a muscle barrier between its belly (abdomen) and chest. That means organs can pass between them. When an organ passes through a muscle barrier, it’s called a hernia.

When a diaphragmatic hernia occurs during fetal development, it affects the way the fetus’s body forms. Its abdominal organs — the stomach, intestines, liver, gallbladder, pancreas and spleen — can shift upward into the chest cavity while everything is still developing. When this happens, the extra organs in the fetus’s chest can end up crowding its lungs and prevent it from growing normally.

Babies born with CDH tend to have small, underdeveloped lungs (pulmonary hypoplasia). This can cause low blood oxygen levels and breathing difficulties at birth. They’ll also have high blood pressure in their lungs, which puts stress on their heart. These babies need critical care at birth to stabilize their condition.

Symptoms of a congenital diaphragmatic hernia

Severe difficulty breathing is the first sign that an infant has CDH. Other congenital diaphragmatic hernia symptoms may include:

• Rapid heart rate (tachycardia)
• Skin discoloration from lack of oxygen (cyanosis)
• Weak breath sounds (usually on one side)
• Bowel sounds in their chest
• Concave belly (abdomen) and barrel chest

Congenital diaphragmatic hernia causes

Physicians don’t know the exact cause of CDH. Research suggests the following factors may play a role in its development:

• Genetics
• Harmful environmental exposure during pregnancy
• Fetal malnutrition

Complications of CDH

Most infants born with a congenital diaphragmatic hernia have small and underdeveloped lungs (pulmonary hypoplasia). This can cause a variety of difficulties, including:

• Low blood oxygen levels (hypoxemia). This affects how all of your baby’s organs function, especially their brain and heart. If it’s severe or persistent, it can cause long-term damage.
• High blood pressure in the arteries of your baby’s lungs (pulmonary hypertension). This condition strains the right ventricle of your baby’s heart and can lead to heart failure.
• Lung infections. Underdeveloped lungs are more vulnerable to infection, like pneumonia. This can be a lifelong problem, even after your baby’s provider repairs their hernia.

Infants with CDH may also have:

• Feeding difficulties. This may result from the pressure put on your baby’s digestive organs or from a difficult birth that required a lot of medical intervention. Babies may require long-term tube feeding and may also have growth faltering.
• Developmental delays. Due to a lack of oxygen, some babies may have developmental delays. They may require physical, speech or occupational therapy over time.
• Sensorineural hearing loss. Some infants with CDH develop progressive hearing loss. Scientists don’t know if this is a complication of the condition, the treatment or both.

How doctors diagnose CDH

Your healthcare provider may find a congenital diaphragmatic hernia during a routine prenatal ultrasound. After discovery, your provider will follow up with a fetal MRI to see the hernia more clearly. They’ll also take a fetal echocardiogram to find out if the fetus’s heart is affected.

Sometimes, your provider doesn’t see a CDH until after your baby is born. Your delivery team may notice signs of respiratory distress or unique body features, like an uneven chest or a barrel chest with a small or concave abdomen. Your providers will follow up with a chest X-ray and an echocardiogram. They may want to take a blood sample to test your baby’s blood oxygen levels and to look for other genetic anomalies.

Rarely, babies born with CDH have no noticeable symptoms. If the hernia is small and causes no major symptoms, healthcare providers may not discover it until later in childhood, or even adulthood.

How is CDH treated?

Congenital diaphragmatic hernia treatment begins as soon as your healthcare provider diagnoses it. These treatments may seem scary, but your healthcare provider is doing everything they can to keep your baby safe.

Prenatal treatment

If your healthcare provider discovers CDH during your pregnancy, they’ll monitor you closely. They’ll look for congenital issues in other organ systems that can be part of a more complex disease. Your provider will also watch for signs of premature labor and decide whether they need to induce your labor early for the sake of the fetus.

In some cases, your healthcare team may be able to treat the fetus before birth. Fetoscopic tracheal occlusion (FETO) is a fetal surgery that, in very specific cases, can help improve the size and function of the fetus’s lungs while it’s still growing. Your provider may use a minimally-invasive surgery called a fetoscopy. A fetoscopy uses a tiny lighted camera called a fetoscope to view the fetus through small cuts (incisions) through your skin and into your uterus.

Through FETO, your provider places a balloon in the fetus’s trachea (windpipe). This allows the amniotic fluid it breathes to build up in its lungs behind the balloon, causing its lungs to expand. This expansion can improve the growth and function of the lungs and reverse some of the damage CDH caused.

Neonatal treatment

Babies who are born with CDH usually require immediate intensive care by a specialized team. If your baby is born with pulmonary hypoplasia (underdeveloped lungs), they’ll need oxygen support first. For some babies, this means a breathing tube attached to a mechanical ventilator.

Other babies may need a more aggressive life support called extracorporeal membrane oxygenation (ECMO). This is a way of bypassing your baby’s underdeveloped lungs and, sometimes, their heart. ECMO draws blood from an artery or vein and adds oxygen to the blood in a machine before sending it back into your baby’s circulation.

Next, your baby will need surgery. Your baby will remain in the neonatal intensive care unit (NICU) until your healthcare team determines that it’s safe to consider surgery. This usually means that pulmonary hypertension has improved and your baby no longer needs ECMO.

For the surgery, a pediatric anesthesiologist will put your baby to sleep with anesthesia. A pediatric surgeon will operate on your baby to move their organs back into their abdomen and repair the defect in their diaphragm. In almost half of all cases, surgeons can use minimally invasive surgery (MIS) through micro 3 mm cuts (incisions) instead of open surgery.

Recovery time

As your baby recovers from surgery, they’ll begin to come off oxygen support. They’ll receive nutrients through a tube until their provider removes the breathing tube. After that, speech and lactation specialists can work with you and your baby to begin mouth feeding. Some babies take longer than others to transition from oxygen support and tube feeding. Your healthcare team will work with you for as long as necessary.

What’s the outlook (prognosis) for children born with congenital diaphragmatic hernia?

The reported survival rate for babies born with CDH has improved. Between 7 and 9 out of every 10 babies survive. These babies are born critically ill, but for those who make it through the tense early days of their condition, the outlook gets better. Some children may have long-term complications, but they’ll still live long and full lives. Continuing advances in medicine improve the odds of both short-term survival and long-term health.

The longer-term prognosis depends on several factors, including:

• If your baby was born prematurely
• How severe your baby’s condition is at birth
• The size of the hernia
• What organs are involved
• Other health conditions

Babies who require breathing or feeding support for longer have a higher risk of ongoing complications, including chronic lung disease, growth failure, hearing loss and developmental delays. Your child’s provider will monitor them closely throughout their early life.