**4.3. Prognosis**

Bilateral pulmonary hypoplasia is fatal. The risk of chromosomal anomalies is rare, but the risk of association with non-chromosomal syndromes is high. A study comparing eight echographic parameters for the prediction of lethal pulmonary hypoplasia showed that the use of the pulmonary area/abdominal circumference and thoracic circumference/abdominal circumference ratio are the most clinically useful in the prediction of bilateral pulmonary hypoplasia [23]. In the case of unilateral pulmonary agenesis, the duration of neonatal survival is higher for the left one in comparison to right one, probably due to the cardiac and mediastinal shift which is with less distortion of the blood vessels and bronchi. The fetuses with unilateral agenesis have a neonatal risk for repeated bronchopulmonary infections and respiratory distress syndrome. The cause of high neonatal mortality is the pulmonary infection and the association with cardiac abnormalities.
