Nonimmune hydrops fetalis in Noonan's syndrome.

Nonimmune hydrops fetalis has been reported to be associated with congenital malformations. We describe two newborns with Noonan's syndrome who presented with nonimmune hydrops fetalis that was most likely secondary to a generalized lymphatic vessel dysplasia. Other manifestations of lymphatic abnormalities in Noonan's syndrome, such as pedal edema and pulmonary and intestinal lymphangiectasis, have been observed in children. Nonimmune hydrops represents one end of the spectrum of abnormalities seen in this syndrome.