Abstract
Pulmonary hypoplasia is often associated with sonographically detectable conditions: oligohydramnios, prolonged premature rupture of membranes, and, not infrequently, fetal anomalies. In their efforts to improve prenatal sonographic diagnosis of this condition, investigators have used an array of different sonographic biometric measurements and fetal behavioral patterns. Definitions of these measurements and their respective successes in predicting pulmonary hypoplasia are presented. The sonographic parameters that have been of most value in the prediction of pulmonary hypoplasia are chest circumference, direct measurements of the lung, lung length, lung span to hemithorax diameter, and more complex formulas, such as lung area/heart area x 100/chest area. Although fetal measurements may help predict pulmonary hypoplasia, no single sonographic finding consistently leads to a prediction of the presence of pulmonary hypoplasia. Therefore, obstetric management (i.e., nonintervention) cannot currently be altered with the finding of abnormal biometric parameters unless a known lethal anomaly is observed.