Congenital diaphragmatic hernia / CDH is most often a posterolateral defect in the left hemidiaphragm (88%) on one side, which leads to herniation of the viscera into the thorax, resulting in pulmonary hypoplasia and respiratory embarrassment.

Congenital diaphragmatic hernia / CDH occurs in approximately 1 in 2,500 to 5,000 live births and as frequently as 1 in 2200 prenatal ultrasound studies.

This discrepancy between neonates who survive birth and transport to a tertiary newborn treatment center and fetuses diagnosed by prenatal ultrasonography supports the notion of a "hidden" mortality.

With inclusion of cases that never reach the treatment stage of disease, the mortality approaches 75%.

Although familial cases with an autosomal-dominant inheritance have been reported, most cases of congenital diaphragmatic hernia / CDH are sporadic.

Associated anomalies are seen in 25% to 57% of all cases of congenital diaphragmatic hernia / CDH and 95% of stillborns with congenital diaphragmatic hernia / CDH and 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% of cases diagnosed prenatally.