Congenital diaphragmatic hernia (CDH) is a condition where a baby is born with a hole in his or her diaphragm. The diaphragm is the muscle that separates the chest from the stomach, and if it does not develop the right way it can be dangerous. When a baby has a hole in their diaphragm, organs like the stomach, liver or intestines can move into the chest where they do not belong. About 1 in 2,500 babies is diagnosed with congenital diaphragmatic hernias each year either during an ultrasound or at birth. If a baby is diagnosed with CDH during an ultrasound, doctors will monitor the pregnancy carefully. Most babies with congenital diaphragmatic hernias can have surgery soon after they are born to repair the diaphragm and return internal organs to their proper place. Sometimes babies may need a ventilator to help them breathe before they are strong enough to have surgery. Outcomes for babies with CDH vary, and depend on how big the hole in the diaphragm is. Once a baby has surgery for CDH he or she will need to be monitored for the rest of its life, but many babies with CDH develop normally.