Objective: To determine whether fetal echocardiography is warranted in cases of single umbilical artery in a population at risk for aneuploidy.
Methods: All cases of fetal single umbilical artery identified over a 2-year period were reviewed for other sonographically detected abnormalities, fetal echocardiographic results, and karyotype.
Results: Sixty-five cases of single umbilical artery were diagnosed on the basis of initial sonograms. Five were subsequently shown to have 3-vessel cords (8% false-positive diagnosis; incidence, 1.2%). Excluding 3 from twin gestations, 57 cases formed the study population. Thirty-one fetuses (54%) were initially thought to have isolated single umbilical arteries, and 26 (46%) had nonisolated single umbilical arteries. Fetal echocardiography was performed in 29 cases (51%), 24 (83%) with normal findings and 5 (17%) with abnormal findings. Four (50%) of 8 nonisolated single umbilical arteries had abnormal echocardiographic findings versus 1 (5%) of 21 apparently isolated single umbilical arteries (P < .05; odds ratio, 20). Karyotypes in 36 cases (63%) showed 25 (69%) euploid and 11 (31%) aneuploid fetuses. An apparently isolated single umbilical artery was never associated with an abnormal karyotype. Eleven (50%) of 22 fetuses with nonisolated single umbilical arteries had aneuploidy (P < .005). The side of the missing umbilical artery did not correlate with other sonographically detected abnormalities, abnormal fetal echocardiographic findings, or aneuploidy.
Conclusions: The rate of cardiac malformations seen with apparently isolated single umbilical arteries is significant, and fetal echocardiography should be performed.