What is congenital diaphragmatic hernia?
The diaphragm is a thin sheet of muscle that separates the chest from the abdomen. In the growing embryo the diaphragm is completely formed by 10 weeks gestation. Approximately 1 in 4000 fetuses have an inborn defect where the diaphragm is incompletely formed. The opening in the diaphragm may allow bowel, stomach or even the liver to enter the chest. This is called congenital diaphragmatic hernia. After birth the hole in the diaphragm can be closed without difficulty. However, in fetal life the abdominal contents that enter the chest leave insufficient space for the lungs to develop normally. When the lungs have insufficient space several parts of the lung that are essential do not develop normally. The little airsac, or alveoli that allow the air to enter the lung are decreased in numbers. The distance between the air entering the lung and the blood vessels that take up the oxygen is increased. The number of blood vessels available to transport oxygen back to the heart are decreased.
