The average baby has two umbilical arteries and one umbilical vein. If there is only one umbilical artery, it is called a single umbilical artery. How does a single umbilical artery affect the fetus? First of all, it should be clarified that fetuses with a single umbilical artery are usually prone to a combination of malformations in other parts of the body, which means that there is a higher incidence of other malformations. When a single umbilical artery is diagnosed, the pregnant woman needs to go to the hospital and have the doctor conduct a detailed examination to see if there are any other structural malformations. If it is simply a single umbilical artery and there are no other malformations, most of these babies develop normally and there is no need to worry. If there are other deformities, it may cause some congenital malformations, and it is necessary to consider the question of whether to carry out an artificial termination of pregnancy.