## **Core Concept**
The umbilical cord typically contains two arteries and one vein. The presence of a single umbilical artery (SUA) is an abnormal finding that can be associated with various fetal anomalies and complications.

## **Why the Correct Answer is Right**
The correct answer, **C. associated with fetal anomalies**, is right because a single umbilical artery is often linked with an increased risk of fetal anomalies, particularly genitourinary and cardiovascular malformations. This condition can be detected prenatally through ultrasound examination. The SUA may result from the absence or atrophy of one of the umbilical arteries. The association with fetal anomalies necessitates a thorough evaluation of the fetus for other potential abnormalities.

## **Why Each Wrong Option is Incorrect**
- **Option A:** Not directly relevant to the common implications of a single umbilical artery. While prematurity can be associated with various umbilical cord anomalies, it is not the most directly related or specific consequence of finding a single umbilical artery.
- **Option B:** This option is incorrect because the finding of a single umbilical artery itself does not directly indicate a need for immediate surgical intervention at birth. Instead, it prompts further evaluation for associated anomalies.
- **Option D:** This option is incorrect because a single umbilical artery is not a normal variant. It is considered an abnormal finding that warrants further investigation.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that the presence of a single umbilical artery is associated with an increased risk of **renal anomalies** in the fetus. Therefore, postnatal renal ultrasound may be recommended for infants with SUA to evaluate for potential genitourinary tract abnormalities.

## **Correct Answer:** C. associated with fetal anomalies.