Single umbilical artery and congenital heart disease in selected and unselected populations

A variable association between single umbilical artery (SUA) and congenital heart disease (CHD) has been reported previously. Discrepancies in the results may be related to the populations studied. In this study we assessed the relationship between SUA and CHD in two well-defined selected and unselected populations.

This was a retrospective review of all cases of SUA detected antenatally in a tertiary referral center between 1997 and 2003. Umbilical arteries were routinely identified around the fetal bladder by color-flow Doppler ultrasonography. The unselected population included pregnancies from a well-defined geographical area, delivering in the same hospital. The selected group was referred from other hospitals because of suspected abnormalities or other risk factors. Major CHD was defined as CHD needing postnatal treatment or long-term follow-up.

There were 10 fetuses with major CHD in the selected group: four cases among 25 with extracardiac defects (16%; 95% CI, 4.5-36.1%) and six cases out of 22 with no other abnormalities (27%; 95% CI, 10.7-50.2%; P = 0.35). In the unselected group there were two cases of major CHD, both among the 13 fetuses with extracardiac abnormalities (15%; 95% CI, 2-45%), while there were no major cardiac defects in the 85 fetuses with SUA and no extracardiac abnormalities (0%; 95% CI, 0-4%; P = 0.03).

The association between SUA and CHD varies dramatically with population selection criteria. The risk for CHD after the detection of SUA in an otherwise apparently normal fetus from an unselected population seems small and may not warrant specialist fetal echocardiography.