Introduction:The presence of a single umbilical artery (SUA) is recognised as a soft marker for congenital anomalies, aneuploidy, earlier delivery and intra-uterine growth restriction and/or low birth weight. The aim of this study was to assess the incidence of SUA in a selected population. And secondly, to examine the clinical significance of this soft marker. Material and methods: A retrospective analysis, over a 36-month period, of all cases of pregnancy interruption due to medical causes, up to 16 weeks of gestation, with prenatal diagnosis of SUA; cases of live born with a prenatal diagnosis of SUA or after delivery, at the routine examination of the placenta. Fetal growth and the risk of preterm labor are also to consider in the surveillance of these pregnancies. Results: Thirty nine cases of SUA were identified during the study period. Incidence of SUA in live born was 0.32% (n=30) and in pregnancy interruption due to medical causes was 12.9% (n=9). The antenatal detection rate was 77%. This ecographic soft marker was an isolated finding in 27 live born (90%). In live born with SUA and associated malformations (13.3%), urinary abnormalities were identified in three cases (75%), and a skeletal with esophageal malformation was identified in one case (25%). Preterm birth occurred in seven cases (23.3%) and birth weight below 10th percentile in four cases (13.3%). Discussion and conclusions: The presence of SUA in antenatal period should alert the sonographer and clinician for the need of a detailed examination of the fetus to exclude other anomalies. Fetal growth and the risk of preterm labor are also to consider in the surveillance of these pregnancies.