Fetal intra-abdominal umbilical vein varix: what is the clinical significance?

Objective To assess the clinical significance of fetal intra-abdominal umbilical vein (FIUV) varix. Methods We reviewed all cases of FIUV varix diagnosed in a university hospital from 1994 to 2003 and searched the English literature for cases of prenatal diagnosis of FIUV varix. The FIUV was considered dilated when the measurements were above 2 SD of the mean for gestational age. Cases reported in the literature were included if the), met the diagnostic criteria for FIUV varix. Results Between 1994 and 2003, 13 fetuses were diagnosed in our hospital as having FIUV varix. Review of the literature revealed an additional 80 cases. Fetal outcome was available for analysis in 91 cases. Additional sonographic abnormalities were detected prenatally in 29 cases (31.9%), most commonly anomalies of the cardiovascular system (including structural and functional abnormalities), hydropic features and anemia. There were nine (9.9%) cases of chromosomal abnormalities. All except one had associated sonographic abnormalities. There were 12 (13%) perinatal losses. Only 54 cases (59.3 %)of fetuses with FIUV varix bad a normal obstetric outcome. In the 62 cases with isolated FIUV varix, there were five unexplained intrauterine deaths (8.1%) occurring between 29 and 38 weeks of gestation. The incidence of complications, which included intrauterine death, thrombosis of the umbilical vein and abnormal antenatal cardiotocogram, were significantly higher (P = 0.01, Fisher's exact test) if the diagnosis of FIUV varix was made before 26 weeks. Conclusions FIUV varix is associated with a high incidence of fetal anomalies and obstetric complications. Detailed sonography is necessary to exclude fetal anomalies. Karyotyping should be offered when additional fetal abnormalities are detected. Intensive surveillance including color Doppler ultrasound should be started from the moment of diagnosis until delivery, especially in those cases presenting early in pregnancy. Copyright (C) 2005 ISUOG. Published by John Wiley Sons, Ltd.