Etiology and outcome of second trimester non-immunologic fetal hydrops.

BACKGROUND: This investigation was undertaken to study the conditions resulting in midtrimester fetal hydrops and to evaluate its overall prognosis as regards counseling purposes.

MATERIAL AND METHODS: The etiology of midtrimester non-immune fetal hydrops was retrospectively evaluated as regards cases detected in singleton pregnancies (n=58) from January 1987 through December 1996. The condition was diagnosed by way of routine biochemical and ultrasonographic screening of a pregnant population.

RESULTS: The rate of diagnosed midtrimester fetal hydrops was 1 in 1700 pregnancies and the overall survival rate in this usually unexpected condition was less than 10%. Various chromosomal and fetal structural abnormalities dominated as a cause of fetal hydrops, representing 44.8% and 43.1% of the cases, respectively. Infection caused only 6.9%. The underlying etiology remained unknown in only three cases. However, in 78% the diagnosis was already known prenatally.

DISCUSSION: Although the overall prognosis is poor, knowledge of the primary etiology is important to determine a rational therapeutic strategy. If the results of routine investigations rule out malformation and abnormal chromosomes, follow-up serial ultrasonographic assessment may indicate that the hydropic state is transient, carrying a somewhat better prognosis.