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Introduction

Varix of the fetal intra-abdominal umbilical vein is a rare entity. The clinical significance of this finding is unclear although in some reports it is associated with poor fetal prognosis. However this anomaly is unlikely to cause major fetal problems¹.

Case report

A  29-year-old, gravida-1, para-1 woman was referred at 22 weeks of gestation and the sonographic evaluation revealed a normal fetal anatomy. A repeat examination at 28 weeks revealed an intra-abdominal cyst measuring 9 mm × 11 mm. Color Doppler revealed venous flow in continuity with the umbilical vein, which was normally connected with the ductus venosus.  A diagnosis of dilatation of the extrahepatic intra-abdominal portion of the umbilical vein was made. The venous flow was present throughout the lesion, suggesting the absence of thrombi.

The follow up examinations at 32 and 34 weeks show a increase in the size of the dilatation: 11 mm × 12 mm at 32 weeks of gestation (Figure) and 13 mm × 14 mm at 34 weeks. The dilation was still isolated with no sign of hydrops but a slight hydramnios was observed.

Premature rupture of membrane occurred at 37 weeks. Caesarean section was performed, due to a unfavorable cervix for vaginal delivery and a healthy 2605 g, girl was delivered, with Apgar scores of 8 and 9 at 1 and 5 min, respectively, and a normal umbilical cord pH.

There is also a 0.5 MB video of the varix.

Discussion

An umbilical vein varix is a focal dilation of the umbilical vein. The diameter of the normal intra-abdominal umbilical vein increases linearly from 3 mm at 15 weeks gestation  to 8 mm at term.  The differential diagnosis with an urachal or an ovarian cyst is easy with the Doppler examination. An umbilical varix is a developmental rather an embryologic abnormality and most cases have a normal ultrasound at 16 to 19 weeks gestation. Unlike persistent right umbilical vein, umbilical vein varices have not been associated with other congenital malformations. The significance of an antenatally detected umbilical varix remains controversial. This finding has been associated with an unexplained high mortality rate in utero: thrombosis of the dilation leading to fetal death and other complications including hydrops fetalis. It had also been linked with chromosomal abnormalities.  The literature gives conflicting results: in the study of Sepulveda² there are 4 fetal deaths (1 trisomy 18, 1 trisomy 9) among 10 cases, but in White’s³ series of 7 cases there were no deaths. The numbers of reported cases is too low to draw definitive conclusion. Serial sonographic evaluation of the fetus³ , with particular attention to the blood flow within the varix, should be carried out.  But Zalel⁵ thinks that delivery must be induced when lung maturity has been accomplished, or any fetal distress is apparent. However, polyhydramnios, hydrops and cardiomegaly do not seem to be the predictors of the fetal outcome.  Karyotyping is not warranted if not any associated malformation is detected.

References

1. Prefumo F, Thilaganathan B and Tekay A. Antenatal diagnosis of fetal intra-abdominal umbilical vein dilatation. Ultrasound Obstet Gynecol 2001;17:82-85

2.Sepulveda W, Mackenna A, Sanchez J, Corral E, Carstens E  Fetal prognosis in varix of the intra-abdominal umbilical vein. J Ultrasound Med 1998;17:171-59

3.White SP, Kofinas A  1994 Prenatal diagnosis and management of umbilical vein varix of the intra-amniotic portion of the umbilical vein J Ultrasound Med 1994;13:992-4

4. Callen PW. Ultrasonography in obstetrics and gynecology 2000; WB Sanders company 4^th edition.p:474-76

5.Zalel Y, Lehavi O, Heifetz S, Aizenstein O, Dolitzki M, Lipitz S, Achiron R. Varix of the fetal intra-abdominal umbilical vein: prenatal sonographic diagnosis and suggested in utero management Ultrasound Obstet Gynecol 2000;16:476-478