ABSTRACT
Hydrops can be divided into immune hydrops, which is due to hemolytic disease in the fetus secondary to maternal anti-red-cell atypical antibodies, and non-immune, which is due to all other causes. Although classically immune hydrops, and in particular rhesus disease, was the most common cause, the introduction of immunoglobulin prophylaxis in at-risk mothers has meant that non-immune causes have become relatively more common. Fetal anemia due to immune causes can be treated by fetal blood transfusions to the fetus, with excellent survival rates and long-term outcome with appropriate treatment. Fetal anemia due to parvovirus infection or fetal-maternal hemorrhage can also often be treated by fetal blood transfusions. Fetal cardiac arrhythmias may be reversed by antiarrhythmic drugs, with resolution of hydrops in many cases. Hydrops due to compression by pleural effusions has been reported to have improved after pleuro-amniotic shunting.
