Investigation of nonimmune hydrops fetalis.

Fifty pregnancies complicated by fetal ascites and generalized edema are reviewed and their prenatal findings, obstetric management, and fetal outcome are discussed. From the myriad of maternal, fetal, and placental problems which are known to cause nonimmune hydrops fetalis, many different causes of the disorder could be identified in 84% of all patients studied by extensive prenatal and postnatal workup. Therefore, in only 16% of the cases was the nonimmune hydrops fetalis labeled "idiopathic." The most common demonstrable causes of the disorder in this series were cardiac anomalies, followed by chromosomal disorders, congenital malformations, alpha-thalassemia, and the twin-twin transfusion syndrome. A systematic approach to the prenatal diagnostic workup of nonimmune hydrops fetalis is outlined, starting with the least invasive techniques (ultrasound, echocardiography, complete blood count, Kleihauer-Betke analysis, TORCH testing, and so forth) followed by more invasive techniques (amniocentesis and fetoscopy). Although the detection and prognostic evaluation of nonimmune hydrops fetalis are greatly improved by applying these techniques, the overall prognosis for most fetuses with nonimmune hydrops fetalis is still very poor, and only a few conditions causing the disorder, such as prenatally detected cardiac arrhythmias or selected cases of urinary tract obstruction, are amenable to treatment in utero.