Quote from "Pediatric Surgery (Springer Surgery Atlas)" by Prem Puri, Michael E. Höllwarth -
"Three easily detectable features—polyhydramnios, mediastinal shift, and the absence of an intra-abdominal stomach bubble—should prompt a more careful search for herniated abdominal organs in the chest. Polyhydramnios is present in about 80% of the pregnancies with fetuses who have CDH and has also been associated with poor outcome. Routine antenatal ultrasound detects approximately 50–85% of cases of CDH. Lung-to-head ratio (LHR), the ratio of contralateral lung area to head circumference, measured by antenatal ultrasound, is used to predict the severity and outcome in CDH and to predict patients with poor outcome for antenatal intervention."
"Three easily detectable features—polyhydramnios, mediastinal shift, and the absence of an intra-abdominal stomach bubble—should prompt a more careful search for herniated abdominal organs in the chest. Polyhydramnios is present in about 80% of the pregnancies with fetuses who have CDH and has also been associated with poor outcome. Routine antenatal ultrasound detects approximately 50–85% of cases of CDH. Lung-to-head ratio (LHR), the ratio of contralateral lung area to head circumference, measured by antenatal ultrasound, is used to predict the severity and outcome in CDH and to predict patients with poor outcome for antenatal intervention."