The single umbilical artery in a high-risk patient population - What should be offered?

Objective. To determine whether fetal echocardiography is warranted in case s of single umbilical artery in a population at risk for aneuploidy. Method s. All cases of fetal single umbilical artery identified over a 2-year peri od were reviewed for other sonographically detected abnormalities, fetal ec hocardiographic results, and karyotype. Results. Sixty-five cases of single umbilical artery were diagnosed on the basis of initial sonograms. Five we re subsequently shown to have 3-vessel cords (8% false-positive diagnosis; incidence, 1.2%). Excluding 3 from twin gestations, 57 cases formed the stu dy population. Thirty-one fetuses (54%) were initially thought to have isol ated single umbilical arteries, and 26 (46%) had nonisolated single umbilic al 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 findi ngs 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 art ery was never associated with an abnormal karyotype. Eleven (50%) of 22 fet uses with nonisolated single umbilical arteries had aneuploidy (P < .005). The side of the missing umbilical artery did not correlate with other sonog raphically detected abnormalities, abnormal fetal echocardiographic finding s, or aneuploidy. Conclusions. The rate of cardiac malformations seen with apparently isolated single umbilical arteries is significant, and fetal ech ocardiography should be performed.