Evidence of endothelium involvement in the pathophysiology of hydrops fetalis?

A fetus with signs of hydrops is at high risk of intrauterine death. The pathophysiology of hydrops fetalis is still unclear. We found decreased concentrations of cyclic guanosine monophosphate in fetal plasma of alloimmunized pregnancies complicated by hydrops fetalis, which might suggest reduced nitric oxide production due to injury of fetal vascular endothelial cells.