Fetal pleural effusion: the risk of fetal trisomy.

Our objective was to review the association between fetal pleural effusion (FPE) and fetal aneuploidy. We conducted a retrospective survey of pregnant women who presented to our ultrasonographic unit between 1990 and 1991, and in whom the diagnosis of FPE was reached. All fetuses had karyotype investigation and a complete ultrasonographic search for associated anomalies. Six cases of FPE were identified. Trisomy 21 was found in 2 (33%). The English literature was reviewed and an additional 147 cases with FPE were collected, among them 6 cases of trisomy 21 and 1 of monosomy 45X. In this accumulated series the risk of aneuploidy in a fetus with an incidental finding of FPE was 5.8% (9 of 153), thus warranting a karyotype study.