ongenital diaphragmatic hernia (CDH) is a birth defect with a high rate of morbidity and mortality. [1][2][3] To optimize outcomes, it is critical that screening ultrasound examinations detect affected fetuses. When CDH is recognized, preparations for delivery at the proper place and time can be made, allowing immediate optimal care of the neonate. [3][4][5] With prenatal diagnosis, the fetus can be fully evaluated, and parents can be appropriately counseled.Since most birth defects occur in low-risk patients, it is critical that sonographers performing screening examinations be aware of signs indicating serious anomalies such as CDH. The most readily recognizable findings with fetal CDH include deviation of the heart to the side of the chest opposite the hernia and, with left sided hernia, displacement of the stomach into the chest. 6 Since these signs are present in almost all cases, it is somewhat surprising that only half of
ORIGINAL RESEARCHObjectives-Deviation of the intra-abdominal umbilical vein has been described as a marker of congenital diaphragmatic hernia (CDH) and has been shown to help identify liver herniation into the fetal chest. The purpose of this study was to quantify the degree of deviation in affected fetuses and to determine the accuracy of measurements for diagnosing liver herniation.Methods-In patients undergoing prenatal sonography for CDH, the midhepatic portion of the umbilical vein was identified, and the distance between the lateral edge of the vein and the inner rib margin was measured. The same was done on the right, and the ratio of the left to right measurement was termed the "umbilical vein ratio." The accuracy of the umbilical vein ratio for predicting the presence and side of the hernia and for diagnosing liver herniation was determined.Results-All but 1 of the cases with right-sided hernias had an umbilical vein ratio above the normal range, and all had liver herniation. Of those with a left-sided hernia, only 2 had a ratio within the normal range. Of those with a left-sided hernia, an umbilical vein ratio less than 0.4 was shown by receiver operating characteristic curve analysis to be the best predictor of liver herniation. This cutoff had sensitivity of 89% for predicting herniation, with a false-positive rate of 14%.Conclusions-Ninety-three percent of right-sided CDH lesions and 98% of left-sided lesions have an umbilical vein ratio outside the normal range. This finding shows that deviation may a useful indicator of CDH in screening ultrasound examinations. An umbilical vein ratio less than 0.4 is predictive of liver herniation.