To the Editor.
— We commend Dr Harrison and colleagues1 for undertaking a thorough study that details the natural history of fetuses with congenital diaphragmatic hernia (CDH). However, it is still impossible to prospectively determine which fetuses or neonates will or will not survive, as only the latter group of patients may be considered for fetal surgical correction of CDH. The major challenge to investigators in this field has been to identify prenatal risk factors in the fetus with CDH that will more accurately predict outcome (and better select candidates for fetal surgery). Although the study by Harrison and colleagues begins to address this challenge, we have several questions.First, subjects enrolled in the study had "isolated CDH" based on "ultrasound studies and karyotypic analysis." Recent studies have suggested that there may be a significant but subtle cardiac disease in CDH, manifested as maldevelopment of the left ventricle.2
Karamanoukian HL, Glick PL. Cardiac Function in Fetuses With Congenital Diaphragmatic Hernia. JAMA. 1994;272(1):29. doi:10.1001/jama.1994.03520010039019