Prenatal ultrasonography frequently fails to diagnose congenital diaphragmatic hernia

Despite increased use of prenatal ultrasonography and well-defined guidelines to aid in the detection of congenital diaphragmatic hernia (CDH), approximately half of neonates born with CDH undergo a prenatal scan that does not diagnose the defect. The purpose of this study was to (1) examine the use of prenatal ultrasonography in neonates with CDH, (2) determine possible reasons that contributed to the failure to detect the abnormality, and (3) evaluate the clinical impact of a diagnostic versus a nondiagnostic study. From 1985 to 1995, 136 consecutive neonates with CDH symptomatic within 24 hours of birth were treated at the University of Michigan Medical Center. Medical records and a University of Michigan CDH database were reviewed for prenatal ultrasound status, side of herniation, site of birth, survival, and extracorporeal life support (ECLS) use. Sonograms that did not diagnose CDH were collected and reviewed by a radiologist for possible reasons why the diagnosis was missed. Over the 10-year period, use of ultrasonography increased from 33% to 100%, but the false-negative rate remained approximately 55%. In reviewing 40 nondiagnostic studies in 25 patients, 25% had technical difficulties, 57% failed to follow established guidelines (localization of the stomach and visualization of the heart with all four chambers), and 33% missed findings (intrathoracic stomach and mediastinal shift) consistent with CDH. There was no significant difference in survival or use of ECLS between neonates with a diagnostic versus nondiagnostic study (53% v 77% survival, P = 0.09; 64% v 42% ECLS, P =.29) Careful attention to following established guidelines and an increased appreciation for the abnormalities would be expected to increase the sensitivity of ultrasonography in detecting CDH. Increased prenatal diagnosis will allow for thorough evaluation for associated malformations detection of chromosomal abnormalities, and early referral with intrauterine transport to a tertiary care center before delivery. Copyright (C) 1997 by W.B. Saunders Company.