Management options for hypoplastic left heart syndrome (HLHS) traditionally included staged surgical palliation to a single-ventricle circulation, neonatal heart transplantation, or termination of pregnancy. Limited data demonstrated a 15-year survival of 39% in patients who received palliative surgery with 64% of deaths occurring at the time of the first surgery.¹ A subset of fetuses with aortic stenosis (AS) have a normal left ventricular size rather than hypoplasia on midgestation echocardiography, but will ultimately develop HLHS at birth. This suggests that the outflow tract obstruction is a potential precursor to HLHS. In utero aortic valvuloplasty, therefore, has the potential to lessen the severity of or prevent progression to HLHS. This study sought to determine features on prenatal echocardiogram that identify appropriate candidates.