erythroblastosis fetalis

or hemolytic disease of the newborn

Anemia in an infant, caused when a pregnant woman produces antibodies to an antigen in her fetus's red blood cells. An Rh-negative woman (see Rh blood-group system) with an Rh-positive fetus whose ABO blood group (see ABO blood-group system) matches hers is likely to have an immune reaction after the first such pregnancy, which sensitizes her when fetal red blood cells enter her bloodstream, usually during labour. If blood typing shows incompatibility, an anti-Rh antibody injection given to the mother after the birth can destroy the fetal red cells, thus preventing trouble in a future pregnancy. If amniocentesis detects products of blood destruction, Rh-negative blood transfusions to the fetus before birth or exchange transfusion after it may save the baby's life. ABO incompatibilities are more common but usually less severe.

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Hydrops fetalis is a condition in the fetus characterized by an accumulation of fluid, or edema, in at least two fetal compartments, including the subcutaneous tissue, pleura, pericardium, or in the abdomen, which is also known as ascites. The edema is usually seen in the fetal subcutaneous tissue, sometimes leading to spontaneous abortion. It is a prenatal form of heart failure, in which the heart is unable to satisfy the insatiable demand for an unusually high amount of blood flow.

Classification and causes

Hydrops fetalis usually stems from fetal anemia, when the heart needs to pump a much greater volume of blood to deliver the same amount of oxygen. This anemia can have either an immune or non-immune cause. Non-immune hydrops can also be unrelated to anemia, for example if a tumor or congenital cystic adenomatoid malformation increases the demand for blood flow.

Immune causes

• Rh disease is the major cause for immune mediated hydrops fetalis; however, owing to preventative methods developed in the 1970s Rh disease has markedly declined. Rh disease can be prevented by administration of anti-D IgG (Rho(D) Immune Globulin) injections to RhD-negative mothers during pregnancy and/or within 72 hours of the delivery.

Non-Immune causes
The non-immune form of hydrops fetalis has many causes including:

• Iron deficiency anemia
• Deficiency of the enzyme beta-glucuronidase. This enzyme deficiency is the cause of the lysosomal storage disease called Mucopolysaccharidosis Type VII.
• Parvovirus B19 (Fifth Disease) infection of the pregnant woman.
• Maternal syphilis.
• α thalassemia can also cause hydrops fetalis when all four of the genetic loci for α globin are deleted or affected by mutation.
• Uncommonly, Niemann-Pick Disease Type C (NPC) can present with hydrops fetalis.
• Turner Syndrome
• Rarely, a tumor. The most common type of fetal tumor is a teratoma, particularly a sacrococcygeal teratoma.

Diagnosis

Hydrops fetalis can be diagnosed and monitored by ultrasound scans.

Treatment

The treatment depends on the cause.

Severely anemic fetuses can be treated with blood transfusions while still in the womb.

See also

• Mirror syndrome

References

Cassidy MD, George. Hydrops Fetalis. eMedicine Online. 2004.

External links

• www.fifthdisease.org Patient Information
• www.hydropsfetalis.org Research Information
• www.hygen.net Case Information & Images
• Hydrops Fetalis Community Forums