Midaortic syndrome in the fetus and premature newborn: a new etiology of nonimmune hydrops fetalis and reversible fetal cardiomyopathy.

Nonimmune hydrops fetalis is the final common pathway of many conditions that ultimately result in fetal anasarca. Even after extensive evaluation, the etiology of a small percentage of cases of hydrops remains unknown. We present a case of midaortic syndrome, also known as abdominal coarctation syndrome, in a fetus with hydrops and a severe cardiomyopathy. The clinical manifestations of midaortic syndrome in this fetus and premature newborn, including malignant hypertension and reversible cardiomyopathy, are detailed. The fetal pathophysiology of midaortic syndrome remains speculative, but likely includes fetal hypertension as the cause of cardiac dysfunction. To our knowledge, this is the first report of midaortic syndrome as an etiology for nonimmune hydrops fetalis.