Prenatal sonographic diagnosis of single umbilical artery

Purpose. We evaluated the reliability of prenatal sonography and the usefulness of the umbilical vein and artery diameter ratio, transverse umbilical artery diameter, and systolic-diastolic ratio in detecting single umbilical artery (SUA). Methods. In 24 of 6,970 fetuses, SUA was detected using prenatal sonography and confirmed at birth. These cases were retrospectively reviewed. Results. Four fetuses had major malformations, and 1 had a minor anomaly. Thirteen fetuses with SUA underwent chromosomal analysis, and only 2 had abnormal karyotypes. Most of the SUA fetuses had a normal systolic-diastolic ratio. Conclusions. Our retrospective study determined that the prognosis of SUA fetuses is good when there is no concurrent anatomic or chromosomal abnormality. Although some reports claim that the transverse umbilical artery diameter or the ratio between umbilical vein and artery diameters can predict SUA, we found no significant improvement in the recognition of SUA using these parameters.