Two-dimensional and three-dimensional ultrasound of fetal anasarca: the glass baby.

Fetal edema was recognized in the past as a complication of alloimmune disease. More recently, fetal edema is frequently seen in conditions that cause non-immune fetal hydrops with increased soft tissue thickness. Classically there is a halo pattern around fetal head, neck, thorax, and abdomen. Fetal edema is associated with karyotype abnormalities, with multiple congenital anomalies, and with certain fetal infections like parvovirus B19 that cause severe fetal anemia. In the present case there was no evidence of infection or karyotype abnormality, but there was hypoplasia of umbilical cord vessels, pulmonary hypoplasia, and pericardial effusion. The etiology of fetal hydrops may remain unknown in up to 30% of cases.