The finding of a single umbilical aery on ultrasound is :
**Core Concept**
A single umbilical artery (SUA) is a congenital anomaly that occurs in approximately 1% of pregnancies. It is associated with an increased risk of fetal growth restriction, preterm birth, and other complications. The presence of a single umbilical artery is often an indicator of underlying chromosomal or structural abnormalities.
**Why the Correct Answer is Right**
The umbilical cord typically contains two arteries and one vein. The two arteries are responsible for carrying deoxygenated blood from the fetus to the placenta, while the single vein carries oxygenated blood from the placenta to the fetus. A single umbilical artery is often an indicator of decreased fetal growth, placental insufficiency, or other underlying fetal anomalies. The mechanism behind this finding is thought to be related to the abnormal development of the embryonic circulation.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** There is no direct correlation between a single umbilical artery and maternal age.
* **Option C:** While a single umbilical artery is associated with an increased risk of fetal anomalies, it is not a direct indicator of fetal demise.
* **Option D:** A single umbilical artery is not typically associated with an increased risk of maternal complications.
**Clinical Pearl / High-Yield Fact**
A single umbilical artery is a significant finding that warrants further investigation, including fetal karyotyping and detailed anatomical survey. It is essential to counsel patients about the increased risk of fetal anomalies and the need for close monitoring throughout pregnancy.
**Correct Answer: C** A single umbilical artery is often associated with fetal growth restriction and an increased risk of fetal anomalies.