++
Key Points
Nonimmune hydrops fetalis is a serious fetal condition in which abnormal fluid accumulates in at least two different fetal compartments, and in which circulating antibodies against red-cell antigens are absent in the mother.
Nonimmune hydrops fetalis is a heterogeneous disorder, caused by a large number of underlying pathologic processes. While the majority of cases appear to be idiopathic, the most common recognizable cause is cardiovascular pathology.
Following the sonographic detection of hydrops, the most important step is to differentiate between immune and nonimmune causes. Once immune causes are excluded, a detailed anatomical survey is needed to rule out congenital abnormalities, which could be the cause of the hydrops.
Nonimmune hydrops can occur secondary to fetal anatomical abnormalities (cardiac, thoracic, gastrointestinal, neurologic, genitourinary, vascular, or skeletal), placental/cord abnormalities, fetal hematologic, neoplastic or metabolic disorders, infection, fetal genetic anomalies, and maternal abnormalities.
Maternal blood tests should include an indirect Coombs antibody screen, maternal blood type, Kleihauer–Betke stain, complete blood count with differential and erythrocyte indices, hemoglobin electrophoresis, and glucose-6-phosphate dehydrogenase deficiency screen. Additional maternal blood work should include TORCH titers, syphilis screen, and parvovirus B19 IgG and IgM titers.
Fetal echocardiography and invasive testing for fetal karyotype should be offered.
While the optimal mode of delivery is uncertain, cesarean section is advised for all potentially viable fetuses due to the risk for soft-tissue dystocia.
Fetal therapy may be possible, including PUBS with transfusion, maternal administration of cardiac medications, and fetal shunt placement.
The long-term prognosis will depend on the nature of the underlying abnormality.
The recurrence risk will depend on the underlying etiology of the nonimmune hydrops.
++
Nonimmune hydrops fetalis (NIHF) is a serious fetal condition in which abnormal fluid accumulates in at least two different fetal compartments, and in which circulating antibodies against red cell antigens are absent in the mother. Hydrops fetalis is associated with a pathologic increase in interstitial and total fetal body water, usually appearing in fetal soft tissues and serous cavities. It may be either immunologic or nonimmunologic, depending on the presence or absence of maternal antibodies against fetal red cell antigens. While it was previously thought that the majority of cases of hydrops fetalis were secondary to maternal–fetal blood group incompatibilities, it is now estimated that over 90% of cases are nonimmunologic (Santolaya et al., 1992).
++
NIHF is a heterogeneous disorder, caused by a large number of underlying pathologic processes. The majority of cases appear to be idiopathic, although some investigators have stated that with thorough investigation an underlying cause can be identified in as many as 84% of cases (Holzgreve et al., 1984;Norton, 1994; Wilkins, 1999). When prenatally diagnosed cases of NIHF and cases of intrauterine fetal death are included, the success rate in discovering an underling cause for NIHF may be as low as 40% (Norton, 1994). The literature on NIHF consists almost ...