Hydrops fetalis is a serious condition in which abnormal amounts of fluid build up in two or more body areas of a fetus or newborn.

See also: Erythroblastosis fetalis

There are two types of hydrops fetalis: Immune and nonimmune. The exact cause depends on which form a baby has.

• Immune hydrops fetalis is a complication of a severe form of Rh incompatibility. Rh compatibility causes massive red blood cell destruction, which leads to several problems, including total body swelling. Severe swelling can interfere with how the body organs work.
• Nonimmune hydrops fetalis occurs when a disease or medical condition disrupts the body's ability to manage fluid. There are three main causes for this type: heart or lung problems, severe anemia (thalassemia), and genetic defects, including Turner syndrome.

The number of babies who develop immune hydrops fetalis has dramatically decreased since the introduction of the medicine RhoGAM, which is used to treat pregnant mothers at risk for Rh incompatibility.

Symptoms depend on the severity of the condition. Mild forms may cause:

• Liver swelling
• Change in skin color (pallor)

More severe forms may cause:

• Breathing problems
• Bruising or purplish bruise-like spots on the skin
• Heart failure
• Severe anemia
• Severe jaundice
• Total body swelling

An ultrasound done during pregnancy may show:

• High amounts of amniotic fluid
• Abnormally large placenta
• Fluid that leads to swelling in the unborn baby's belly area and organs, including the liver, spleen, heart, or lung area

An amniocentesis and frequent ultrasounds will be done to determine the severity of the condition.

Treatment depends on the cause. During pregnancy, treatment may include:

• Medicine to cause early labor and delivery of the baby
• Early cesarean delivery if condition gets worse
• Intrauterine fetal blood transfusion

Treatment for a newborn may include:

• Direct transfusion of packed red blood cells (compatible with the infant's blood type) and an exchange transfusion to rid the baby's body of the substances that are destroying the red blood cells
• Needle aspiration to remove extra fluid from around the lungs and belly area
• Medicines to control congestive heart failure and help the kidneys remove extra fluids
• Methods to help the baby breathe, such as a breathing machine

Hydrops fetalis often results in death of the infant shortly before or after delivery. The risk is highest among the most premature babies and those who are severely ill at birth.

A form of central nervous system damage called kernicterus may occur.

Rh incompatibility, which can lead to this condition, can be prevented if the mother takes a medicine called RhoGAM at certain times during and after pregnancy.

Abrams ME, Meredith KS, Kinnard P, Clark RH. Hydrops fetalis: a retrospective review of cases reported to a large national database and identification of risk factors associated with death. Pediatrics. 2007 Jul;120(1):84-9.

Kumar V, Abbas AK, Fausto N. Robbins and Cotran Pathologic Basis of Disease. 7th ed. St. Louis, Mo: WB Saunders; 2005.