IN normal pregnancy, the fetal umbilical cord contains three umbilical blood vessels. Two umbilical arteries, and one umbilical vein. Even one umbilical artery is needed to handle blood supply to placenta.
The cause of single umbilical artery is unknown.
Normal fetus will have three blood vessels. But 1 to 5 % babies will have only two blood vessels, one umbilical artery, and one umbilical vein. This is called single umbilical artery.
The ultrasound scan confirms the single umbilical artery. If the fetus doesn’t show any abnormalities, the baby will take normal birth.
Some studies says the 25 % single umbilical artery baby may have chromosomal abnormalities. If single umbilical artery is confirmed during ultrasound scan, tests such as Amniocentesis and others are done for further diagnosis.
Single umbilical artery baby may have or may not have any other abnormalities.