The umbilical cord is an important part of the fetoplacental unit. Single umbilical artery (SUA) is the most frequent anomaly, not only of the umbilical cord but probably among all birth defects. When there is only one umbilical artery in an umbilical cord it is called single umbilical artery. Many abnormalities of cord length and low placental weight have been associated with SUA. Fetal anomalies included are; diaphragmatic hernia, gastrointestinal, cardiac, musculoskeletal and renal anomalies. SUA is included in pathognomic feature of Sirenomelia. Fetal growth restriction is common in them due to anomalies, chromosomal abnormalities and impaired placental development and perfusion. Perinatal morbidity and mortality are increased mainly due to underlying
structural and chromosomal anomalies. When SUA is diagnosed , prompt search should be made to detect other associated anomalies in the baby.