Congenital Diaphragmatic Hernia / CDH is a defect in the diaphragm of the fetus. Most often (88 percent) Congenital Diaphragmatic Hernia / CDH is a posterolateral defect in the left hemidiaphragm on one side. This leads to herniation of the viscera into the thorax, resulting in pulmonary hypoplasia and respiratory embarrassment.
Associated anomalies are seen in 25 to 57 percent of all cases of Congenital Diaphragmatic Hernia / CDH and 95 percent of stillborns with Congenital Diaphragmatic Hernia / CDH.
These anomalies include congenital heart defects, hydronephrosis, renal agenesis, intestinal atresia, extralobar sequestrations and neurologic defects, including hydrocephalus, anencephaly, and spina bifida.
Chromosomal anomalies, including trisomy 21, 18, and 13, occur in association with Congenital Diaphragmatic Hernia / CDH in 10 to 20 percent of cases that are diagnosed prenatally.