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Counseling and management of prenatally diagnosed nonimmune hydrops.


Describe the current investigations and management of nonimmune fetal hydrops with a focus on treatable or recurring etiologies.


Hydrops fetalis is defined as an abnormal accumulation of fluid in at least two different fetal compartments. Generally it carries a poor prognosis; however, several etiologies can be treated in utero with potential good results. The growing number of recognized etiologies requires a comprehensive and systematic search for causes, in particular, for treatable or recurrent conditions.


  1. All pregnant women with fetal hydrops should be referred promptly to a maternal-fetal medicine unit for evaluation. Some conditions amenable to prenatal treatment represent a therapeutic emergency after 18 weeks.

  2. Fetal chromosome analysis through comparative genomic hybridization microarray molecular testing should be offered in all cases of nonimmune fetal hydrops.

  3. Imaging studies should include comprehensive obstetrical ultrasound (including arterial and venous fetal Doppler) and fetal echocardiography.

  4. To evaluate the risk of fetal anemia, Doppler measurement of the middle cerebral artery peak systolic velocity should be performed in all hydropic fetuses after 16 weeks of gestation. In cases of suspected fetal anemia, fetal blood sampling and intrauterine transfusion should be offered rapidly.

  5. Investigation for maternal-fetal infections, and alpha-thalassemia in women at risk based on ethnicity, should be performed in all cases of unexplained fetal hydrops.

  6. All cases of unexplained fetal hydrops should be referred to a medical genetics service where available. Detailed postnatal evaluation by a medical geneticist should be performed on all cases of newborns with unexplained nonimmune hydrops.

  7. Autopsy should be recommended in all cases of fetal or neonatal death or pregnancy termination. Amniotic fluid and/or fetal cells should be stored for future genetic and/or metabolic testing.


Hydrops fetalis is defined as an abnormal accumulation of fluid in at least two different fetal compartments. It implies an extracellular accumulation of fluid in tissues and serous cavities. It generally presents as subcutaneous edema, accompanied by effusions in two or more serous cavities, including pericardial or pleural effusions and ascites. Polyhydramnios or placental thickening (>6 cm) is often associated. The primary mechanisms associated with hydrops fetalis are anemia, heart failure, increase of central venous pressure/compromised venous return, and hypoproteinemia.


Maternal red cell alloimmunization occurs when a pregnant woman presents an immunological response to a paternally-derived antigen that is foreign to the mother and inherited by the fetus. Maternal antibodies may cross the placenta, bind to antigens present on the fetal erythrocytes, and cause hemolysis, hydrops fetalis, and fetal death. The complete description and management of this condition is beyond the scope of this chapter.


Nonimmune hydrops ...

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