Value of autopsy in nonimmune hydrops fetalis: series of 51 stillborn fetuses

Nonimmune hydrops fetalis (NIHF) is used to describe fetuses and newborns with generalized edema and cavity effusions. It is helpful to alert physicians about the presence of anemia, heart failure, and/or hypoproteinemia, but this diagnosis is frequently overlooked. We reviewed the autopsy files from 1990 to 2000, selected all cases with NIHF including clinical information (with maternal laboratory tests and ultrasound), and classified patients by etiology. Among 840 stillborn autopsies during the 11-year period, we found 51 with NIHF (6.07%). The clinical summary had mentioned hydrops in 14 patients and the etiology in another 7 by fetal ultrasonography, but without addressing the possibility of hydrops. In the remaining 30 cases neither hydrops nor an etiology was mentioned. Other pertinent diagnoses were maternal diabetes mellitus (4), congenital heart disease (3), and cystic hygroma (2). The following diagnoses were made in one instance each: cardiac tumor, twin transfusion syndrome, congenital adenomatoid malformation, syphilis, Turner syndrome, and cerebral arteriovenous malformation. Postmortem and placental examination confirmed the following etiologies: congenital infections (17); placental pathology significant enough to explain NIHF (10); cardiovascular diseases (8) (further classified as congenital heart disease [3], rhabdomyoma [1], and vascular malformations [4]); chromosomal abnormalities (6); uncontrolled maternal diabetes (4); intrathoracic lesions (2); prune-belly syndrome (2); and idiopathic NIHF (2). Only 3.9% of the cases studied had no identifiable etiology. The cause of hydrops was confirmed by autopsy in 47 fetuses (92%), which further supports the importance of performing an autopsy. Thirty-two cases (62.74%) had placental abnormalities helpful to the etiology (parvovirus, syphilis, Turner's syndrome, etc.). In 20 instances, the clinical summary had no mention of either hydrops or any of the diseases leading to it. The autopsy in conjunction with placental examination and fetal ultrasound represent the best combination to determine the etiology of NIHF among stillborn fetuses.