Fetal edema (abnormal fluid buildup), also known as hydrops fetalis, is a serious condition that causes body swelling in a fetus or newborn. There are two types of hydrops fetalis: immune and nonimmune. Immune hydrops fetalis is caused by a severe Rh incompatibility between mother and fetus. The mother has an Rh negative blood type that makes antibodies that attack the fetus’ Rh positive blood cells and destroys them leading to severe swelling that affects the fetal organs. Nonimmune hydrops fetalis is the more common type (90%), which occurs when the fetus or newborn has a disease or medical condition, such as heart or lung disorders, severe anemia, blood conditions or infections, or genetic or developmental problems. Hydrops fetalis can be mild or severe.

Symptoms of mild forms of hydrops fetalis include swelling of the liver and pale skin. Symptoms of the more severe forms include total body swelling, breathing difficulties, bruising, severe anemia and jaundice (yellowing of the skin and whites of eyes), and heart failure.

Treatment for hydrops fetalis depends on the cause. During pregnancy, intrauterine blood transfusions may be given, or early delivery may be warranted. Treatment for the newborn with immune hydrops fetalis may include exchange transfusions to eliminate the mother’s antibodies that are destroying the baby’s red blood cells, fluid removal (aspiration), diuretics and heart medications, and mechanical ventilation. In severe cases of Rh incompatibility, a form of brain damage known as kernicterus may occur as well as developmental delays. However, prevention of Rh incompatibility can be effected with the administration of RhoGAM to the mother both during and after pregnancy.