Idiopathic hydrops fetalis report of 4 patients including 2 affected sibs.

We report four patients with idiopathic hydrops fetalis (IHF), two being affected sibs; the latter represent the first reported familial occurrence. A review identified 45 additional cases that seem to represent 1/3 to 2/3 of all cases of hydrops fetalis of nonimmunologic origin (NIHF). Our patients and the other adequately documented cases permit delineation of "idiopathic" fetal hydrops; ie, that form of the condition which is not associated with any detectable fetal or maternal disorders. These fetuses are usually premature, often the product of a gestation complicated by pre-eclampsia, occasional maternal anemia, and most often polyhydramnios. The fetuses have striking edema of most tissues with effusions into serous cavities, but no other specific anatomic abnormalities. They are often hypoproteinemic, but not anemic and do not manifest signs of accelerated hematopoiesis. Results of fetal and maternal immunohematological examination are normal. Fetal mortality rates approach 100% but recent data suggest that salvage rates can be significantly improved with early diagnosis. This requires accurate diagnosis and all factors and conditions known to be associated with other types of NIHF should be excluded. A relationship between fetal hypoalbuminemia and IHF may exist and needs further investigation, IHF is sporadic in most instances; however, recessive inheritance may be indicated by occurrence in two sibs. IHF represents a distinct, frequently unrecognized and relatively common entity in need of further study and increased recognition.