Incidence: In the past the most common cause of
immune hydrops fetalis was Rh isoimmunization. Since the advent
of anti-D globulin prophylaxis the incidence of immune hydrops
has decreased significantly. Nowadays most cases of hydrops fetalis
are nonimmune in nature. The incidence of nonimmune hydrops in
Europe and the United States is approximately 1:2500 – 4000 newborns.
Parvovirus B19 infection, fetomaternal transfusion and
twin-to-twin transfusion are quite common. The indicence of
hydrops fetalis, up to 1:500 pregnancies, is very high in the
Southeast Asia as a consequence of homozygous α thalassemia.
Prognosis: General mortality of hydrops fetalis is 60 – 90%.
Stillbirth is frequent. The cause of death of a hydropic infant
is respiratory insuficiency due to pulmonary hypoplasia.