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Congenital lung malformations

Fetal pregnancy complications


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Congenital lung malformations diagnosed in pregnancy affect approximately 4 in 10,000 births and commonly have a good prognosis.

They are divided into two categories: hyperechoic lesions such as lung sequestration and lobar emphysema; and single or multiple cystic lesions such as bronchogenic cyst and cystic adenomatoid malformation of the lung.

In more than 90% of cases, only one lung is affected by the malformation. It is very rare that this type of congenital malformation increases the risk of antenatal or postnatal morbidity or mortality.


Cystic lesions are most often caused by abnormal development of parenchymal lung cells.

Hyperechoic lesions may be caused by bronchial atresia [ks1] or inflammation of the alveolar tissue.

Symptoms to monitor

Fetal monitoring depends on whether the lesions have cysts or not.

The regression or even disappearance of a lesion is common during pregnancy. Radiological monitoring is however recommended in the weeks following birth.

On the other hand, close ultrasound monitoring is recommended for micro-cystic lesions in order to monitor and prevent the development of hydrops in the fetus. Hydrops is the accumulation of fluid in the subcutaneous tissues and/or organs of the fetus, causing an increase in cardiac output that can lead to heart failure.

Tests and procedures

No gene has been described as being responsible for these congenital lung malformations, but genetic counseling may be required depending on the situation.

In the majority of cases, congenital lung malformations are diagnosed during a routine morphological ultrasound around week 20.

When a congenital lung malformation is suspected, a consultation in a specialized centre such as CHU Sainte-Justine is recommended to determine the type of lesion. Once the type of malformation is identified, ultrasound tracking of the lesion can be established.

Treatment and follow-up care

When the suspected lesion is at risk of rapid proliferation, an ultrasound will be scheduled every 10 to 14 days. For more stable lesions, checking every 3 to 4 weeks is recommended.

The evaluation of the mother and unborn baby is done by a multidisciplinary team that includes an obstetrician specializing in fetal-maternal medicine, a pediatric surgeon, a neonatologist pediatrician, and a radiologist. Several other professionals such as a psychologist can also be part of the team, depending on individual needs.

Pregnancy follow-up and delivery should be done in a specialized tertiary centre such as CHU Sainte-Justine unless otherwise advised by specialists during pregnancy follow-ups.

If the lesion has regressed and is no longer visible on ultrasound, delivery at CHU Sainte-Justine is not necessary, however postnatal recommendations will be given to the pediatrician at the hospital of choice.

Resources and useful links

Robert K. Creasy et Robert Resnik. Maternal-Fetal Medecine : Principle and Practice, 7th edition, Elsevier, 2014.

Page by

Chantal Larcher, inf. clinicienne et Dre Lucie Morin

About this page
Updated on 1/25/2021
Created on 12/19/2017
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