Congenital High Airway Obstruction (CHAOS)

Congenital high airway obstruction (CHAOS) is a complete or nearly complete obstruction of the fetal airway.

The obstruction can be due to a variety of causes including:

  • a cyst in the larynx
  • a membrane that blocks the larynx or trachea
  • a malformation that closes off the trachea or larynx
  • a narrowing of the glottis (the middle part of the larynx)

This obstruction causes some serious problems in the fetus:

  • swelling of the lungs
  • swelling of the trachea and bronchial tubes
  • heart failure

Prenatally diagnosed CHAOS requires intervention sometime before your baby takes his first breath.

How often does congenital high airway obstruction occur?

CHAOS was once thought to be extremely rare. Yet, more than a dozen cases have been reported since 1989.

Researchers believe that CHAOS may be more common than they realized, since many fetuses affected with this condition either do not make it to term or are born without being diagnosed.

What causes congenital high airway obstruction?

No one knows. It occurs by chance. No hereditary basis has been identified.

Hope and compassionate care

The Maternal Fetal Care Center (MFCC) of Boston Children's Hospital is making a significant difference in the outcomes for families facing complex birth defects and other critical challenges to the health of their fetus or newborn.

We've got the expert physicians and staff to significantly improve outcomes for babies with complex health concerns like CHAOS, while delivering hope and compassionate care to families along the way.