Why Does a Fetus Develop a Single Umbilical Artery?

A normal umbilical cord should have one umbilical vein and two umbilical arteries. If there is only one umbilical artery, it is called a single umbilical artery, which is a common umbilical cord abnormality.

The causes of a single umbilical artery are complex and may be related to the mother's smoking habits, diabetes, high blood pressure, or seizure disorders.

A single umbilical artery may occur early in embryonic development, or it may start as two normal umbilical arteries, but one artery becomes underdeveloped or atrophies during development, resulting in a single umbilical artery [1].

What Should You Do If an Ultrasound Shows a Single Umbilical Artery?

If the ultrasound only detects a single umbilical artery without any other structural abnormalities, the newborn is usually healthy after birth—meaning the fetus is no different from a normal one.

If other structural abnormalities are also found on the ultrasound, the risk of chromosomal abnormalities or other malformations in the fetus increases.

If a single umbilical artery is diagnosed by ultrasound, doctors will generally recommend that the expectant mother undergo a fetal echocardiogram to rule out any related developmental abnormalities in the baby's heart.