Embryology · Respiratory system, diaphragm and body cavities
Congenital diaphragmatic hernia !
- Malformation
Through a hole in the diaphragm, bowel and organs rise into the fetal chest and squash the lung, which fails to grow. At birth the baby struggles to breathe.
Updated 2026-11-01
See it in 3D: Diaphragm · Phrenic nerves · Stomach · Spleen · Left lower lobe
What it is
Congenital diaphragmatic hernia is a defect of the diaphragm through which abdominal organs enter the chest during fetal life. The typical (Bochdalek) form comes from incomplete closure of the pleuroperitoneal membrane, nearly always on the left. What makes it severe is not the hole but the pulmonary hypoplasia and pulmonary hypertension it leaves; it affects about 1 in 2,500 newborns.
Embryological cause
- The pleuroperitoneal membranes should close the pericardioperitoneal canals around week 7.
- If a membrane fails to close or to become muscular, a posterolateral hole remains (Bochdalek).
- When the gut returns from the umbilical cord (around week 10), loops can rise through the hole into the chest.
- The organs compress the lung during the pseudoglandular and canalicular stages: fewer bronchial branches, alveoli and vessels.
- The left side closes later than the right, so most hernias are left-sided.
How it presents
- Respiratory distress and cyanosis from the first minutes of life.
- Scaphoid (sunken) abdomen because the organs are in the chest.
- Heart sounds shifted to the right and bowel sounds in the left hemithorax.
- Persistent pulmonary hypertension with hypoxaemia that is hard to correct.
- May come with heart defects, chromosomal anomalies and syndromes such as Fryns or Pallister-Killian.
Diagnosis
- Prenatal ultrasound: stomach or bowel loops in the chest and a displaced heart.
- Lung-to-head ratio and fetal MRI to estimate lung volume and outlook.
- X-ray at birth: air-filled loops in the hemithorax and a gastric tube above the diaphragm.
Test yourself
Think of the answer, then tap the question to see it.
Which embryonic structure fails in a Bochdalek hernia?
The pleuroperitoneal membrane, which fails to close the pericardioperitoneal canal, nearly always on the left.
What sets the outlook in congenital diaphragmatic hernia?
The degree of pulmonary hypoplasia and pulmonary hypertension, more than the size of the hole.
What does examination show in a newborn with a left diaphragmatic hernia?
Respiratory distress, a scaphoid abdomen, bowel sounds in the left chest and heart sounds shifted to the right.
Why is a newborn with diaphragmatic hernia not ventilated with bag and mask?
Because air enters the herniated stomach and bowel, distends them and compresses the lung even more.
See it in 3D
The structures of Durgical's 3D anatomy where it is found.
Related
- Diaphragm: its four components and its innervation
- Pulmonary hypoplasia
- Intraembryonic coelom: pericardial, pleural and peritoneal cavities
- Lung development: the five stages
- Midgut: physiological herniation and rotation
- Prenatal diagnosis: ultrasound, serum screening, cell-free DNA, CVS, amniocentesis
Related conditions
Educational content on embryonic development; not a guide to prenatal diagnosis or to medicines in pregnancy and no substitute for a health professional's advice. No doses are given.
Sources: Congenital diaphragmatic hernia: MedlinePlus Genetics (MedlinePlus, U.S. National Library of Medicine, 2019); Diaphragmatic hernia: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2025); Langman's Medical Embryology, 13th ed., ch. 7: The Gut Tube and the Body Cavities (Wolters Kluwer, 2015).
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Representative model, for educational purposes only.