What is CDH, really?

This page is educational and is not medical advice. It cannot replace a conversation with your own care team. If you have an urgent concern, call your physician or 911.

Module 1 — Starting the Journey · Episode 1

The short version

The diaphragm is the dome-shaped muscle that separates the chest from the belly, and it is what moves when you breathe. In congenital diaphragmatic hernia, or CDH, that muscle does not finish forming during early pregnancy, leaving an opening. Through it, organs that belong in the abdomen, such as the intestines, stomach, and sometimes the liver, can move up into the chest.

“Congenital” means present at birth. “Diaphragmatic” refers to the diaphragm. “Hernia” means something has pushed through an opening where it should not be.

Why it matters for the lungs

The biggest concern in CDH is usually not the opening itself, but what it does to the lungs. While the lungs are still growing before birth, the organs crowding into the chest leave less room for them to develop, so they can end up smaller and less mature than they should be. This is pulmonary hypoplasia, or underdeveloped lungs.

The blood vessels in the lungs can also be affected, making it harder for the heart to pump blood through them after birth. This is pulmonary hypertension. Together, small lungs and high pressure in the lung vessels are the main reasons CDH can be serious, because a newborn must breathe on its own the moment it is born.

How common is it, and why did it happen?

CDH occurs in roughly 1 in every 2,500 to 3,000 births. In the large majority of cases, nothing the parents did caused it. Most cases happen sporadically, by chance, as the diaphragm forms in the first weeks of pregnancy. CDH can occur on its own (isolated) or alongside other findings, which is why your team may recommend additional testing.

Left side, right side

Most CDH occurs on the left side, where the diaphragm tends to be weakest. Right-sided and both-sided CDH are less common. Severity varies widely, and how it is estimated is covered in the next episode.

The hopeful part

CDH is serious, but it is also a condition where care has improved substantially and where active research, including the work in this lab, is focused on doing better still. Many children with CDH go on to live full lives.

Next in Module 1: How severity is estimated · Back to Module 1