Fetal diaphragmatic hernia is a congenital defect that develops during the formation of the diaphragm, the muscular shelf that separates the chest cavity from the abdominal cavity. The diaphragm is the muscle that helps us to breathe, so it is a critical component of the respiratory system. In a diaphragmatic hernia, the diaphragm — which develops at about 8–10 weeks of pregnancy — does not completely form, and a gap is created between the chest and the abdominal cavity.
The severity of this condition ranges from a small gap in the diaphragm to no diaphragm on one side of their body. Ninety percent of all defects are found on the left side of the diaphragm. Depending on how large the hole is, the intestines, spleen, liver and/or stomach may move up into the chest cavity. In turn, this causes the lungs to develop poorly so that the baby is born with a smaller number of air sacs, blood vessels, and airways. When this happens, breathing can be difficult or impossible.
It is estimated that one in every 2,200 births is affected by diaphragmatic hernia. Parents that have one child born with a diaphragmatic hernia are at an increased risk of having another child with this condition; their chance is approximately one in every 50. Also, infants with this condition are likely to have other birth defects. About one in five are born with heart defects, and one in 10 are born with genetic abnormalities.
How Is Fetal Diaphragmatic Hernia Diagnosed?
A fetal diaphragmatic hernia can be diagnosed by ultrasound (sonogram) examination prior to birth. Evaluation of the chest and abdominal area is part of the routine ultrasound examination done by many obstetricians as part of their routine prenatal care around the 20th week of pregnancy.
Additionally, it is recommended that a baby diagnosed with this condition be referred to a pediatric cardiologist to undergo a fetal echocardiogram, which is an ultrasound of the infant's heart while still in the womb. This is performed because many babies born with a diaphragmatic hernia also have congenital heart defects. The echocardiogram provides a much more in-depth evaluation of the heart. Sometimes magnetic resonance imaging (MRI) is performed to view the area better.
How Is Fetal Diaphragmatic Hernia Treated?
After fetal diaphragmatic hernia is diagnosed, our staff counsels the parents and prepares them for what to expect when their baby is born. Plans are made to assure that the baby is delivered in a hospital that has a neonatal intensive care unit (NICU) with a neonatologist present at the delivery.
After birth, the baby is stabilized and then transferred via ambulance to Lurie Children’s to begin treatment. Often the newborn is unable to breathe on their own because of poor lung development. Most babies need help from a breathing machine called a ventilator.
After stabilization (generally 1–2 weeks), the infant has surgery to repair the diaphragmatic hernia. This is done either by closing the hole with stitches in cases of a small defect; in larger defects, the surgeons may have to place a sheet of mesh graft into the baby's chest to close the hole. In carefully selected cases, these surgeries can be completed using the “minimally invasive surgery” technique, thus avoiding a large incision.
If an infant cannot be stabilized while on the ventilator, they may be temporarily placed on a heart/lung bypass machine called extracorporeal membrane oxygenation (ECMO). This machine helps to pump blood and bring oxygen to the rest of the body. Few babies need the assistance of ECMO because neonatal care has significantly improved over the last 20 years. However, if a child does need to rely on it for a short time, he will undergo an operation to attach the tubes of the ECMO to his blood vessels.
What Are the Long-term Effects of Fetal Diaphragmatic Hernia?
It depends on the amount of functional lung tissue present, the size of the hole in the diaphragm and whether or not the child is born with other birth defects or genetic problems. Some babies have long-term problems and need regular follow-up care after they return home. Some of the medical problems can include high-frequency hearing loss, chronic lung disease, gastroesophageal reflux disease and other developmental problems. Many of these problems can be treated with medications and therapy — allowing the child to have a better quality of life. Furthermore, diagnosing the problem before birth increases their chances of survival and a longer life expectancy since treatment can begin as soon as they are born.