Ultrasonographic prediction of lethal pulmonary hypoplasia: comparison of eight different ultrasonographic parameters.

OBJECTIVE: The aim of this study was to determine the usefulness of eight different ultrasonographic fetal parameters for predicting fetal pulmonary hypoplasia.

STUDY DESIGN: Nomograms of eight different ultrasonographic fetal parameters were evaluated by studying uncomplicated single fetus pregnancies with well-established dates between 18 and 40 weeks of gestation. The eight parameters, which could reflect fetal lung mass, were as follows: thoracic circumference, thoracic area, thoracic area minus heart area, lung area, thoracic circumference/abdominal circumference ratio, thoracic area/heart area ratio, thoracic area minus heart area/thoracic area ratio and lung area/thoracic area ratio. The relative efficacy of the eight parameters was determined by studying 21 fetuses at high risk for development of lethal pulmonary hypoplasia and 30 fetuses with premature rupture of membranes within 1 week.

RESULTS: The lung area (gestational age-dependent parameter) and the thoracic circumference/abdominal circumference (gestational age-independent parameter) ratio had the best diagnostic accuracy (sensitivity 81.3% and 90.5%, specificity 100% and 90.0%, positive predictive value 100% and 86.4%, negative predictive value 90.9% and 93.1%, respectively). There were significant linear relationships between lung weight and lung area and between the lung weight/body weight ratio and the thoracic circumference/abdominal circumference ratio.

CONCLUSION: These data suggested that the application of lung area and the thoracic circumference/abdominal circumference ratio are clinically useful for the evaluation of fetal pulmonary hypoplasia.