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The umbilical cord is the lifeline connecting the baby to the placenta during pregnancy allowing for the transfer of nutrients, oxygen, and waste products. In a recent episode of the “Healthful Woman” podcast, Dr. Simi Gupta, an expert in maternal-fetal medicine, joined Dr. Nathan Fox to discuss common umbilical cord issues that can be detected during pregnancy through ultrasounds.

The Role and Structure of the Umbilical Cord

The umbilical cord is a vital component of fetal development. It typically contains three blood vessels—one umbilical vein that delivers oxygenated blood and nutrients from the placenta to the baby and two umbilical arteries that carry waste products back to the placenta. The cord is encased in a protective, jelly-like substance called Wharton’s jelly, which cushions the vessels and prevents them from being compressed.

Common Umbilical Cord Abnormalities

During a routine ultrasound, doctors assess the umbilical cord for abnormalities, focusing on how the cord inserts into the placenta and the number of vessels present. Dr. Gupta states, “The umbilical cord is something that we clearly assess on every ultrasound, and we document if it’s abnormal. And, of course, if it’s abnormal, we talk to our patients about it.” Dr. Gupta highlighted common issues that can arise.

Marginal Cord Insertion

This occurs when the umbilical cord attaches to the edge of the placenta rather than the center. While it is relatively common, occurring in about 6% of pregnancies, it is generally not associated with significant complications. Dr. Gupta reassures that in most cases, this is considered a normal variant and may require an additional ultrasound for fetal growth or just routine monitoring.

Velamentous Cord Insertion

A more concerning condition is velamentous cord insertion, where the umbilical cord attaches to the membranes instead of the placenta. This condition, seen in 1% to 2% of pregnancies, can lead to complications such as growth restriction or, in rare cases, stillbirth. Dr. Gupta emphasizes the importance of monitoring the baby’s growth and overall health more closely in these cases, typically through regular ultrasounds.

Single Umbilical Artery (Two-Vessel Cord)

Typically, the umbilical cord has two arteries and one vein. However, in some cases, one of the arteries may be absent, resulting in a two-vessel cord. This condition is also relatively common, occurring in about 1% of pregnancies. Like velamentous cord insertion, a two-vessel cord can be associated with a slightly increased risk of growth restriction and stillbirth, though the overall risk remains low. It can also be associated with congenital heart defects.  Dr. Gupta advises that, in these cases, expectant parents should be reassured but vigilant, with a fetal echocardiogram which is a special ultrasound of the heart to look for congenital heart defects, regular growth scans, and monitoring to ensure the baby’s well-being.

Cord Coiling and Its Implications

The umbilical cord is often coiled or twisted, similar to a rope. While variations in coiling are generally benign, there are instances where a cord might be hyper-coiled (too tightly twisted) or hypo-coiled (too loosely twisted). Dr. Gupta notes that while these variations can be observed, they are not routinely measured during pregnancy.

The Significance of the Cord Around the Baby’s Neck

One of the most common concerns among expectant parents is whether the umbilical cord is wrapped around the baby’s neck. Dr. Gupta addresses this by explaining that this situation, known as a nuchal cord, is actually quite common, occurring in about 20% of pregnancies. In most cases, it does not pose a threat to the baby and does not require any intervention. She also highlights that diagnosing this condition via ultrasound is not always reliable, and it generally does not alter pregnancy or delivery.

Learn More

To learn more, listen to the “Healthful Woman” podcast. If you have concerns about your pregnancy or would like to learn more about how umbilical cord issues might affect you, consult with your healthcare provider at Carnegie Imaging in New York. Contact us today through our online contact form.

Carnegie Imaging for Women blogs are intended for educational purposes only and do not replace certified professional care. Medical conditions vary and change frequently. Please ask your doctor any questions you may have regarding your condition to receive a proper diagnosis or risk analysis. Thank you!