11/03/2025
What is a "true knot" in the umbilical cord? ➰🤔
A true knot is exactly that- a knot tied in the umbilical cord. This is rare, occurring in 1-2% of pregnancies, although we have seen at least 4 true knots so far this year at the birth center. A true knot occurs when a baby has moved in way that creates a loop in the umbilical cord that then forms a knot.
True knots can potentially cause problems by restricting blood flow to the baby, which can lead to growth restriction, fetal distress, and other complications. However, most of the time the blood vessels in the umbilical cord are protected from being compressed by the thick jelly that lines the inside of the cord.
Wharton's jelly is the thick, gelatinous connective tissue that appears white after the cord has stopped pulsating. This jelly provides protection and insulation of the blood vessels (2 arteries and 1 vein) inside the cord that supply the baby with oxygen and nutrients. The jelly helps prevent compression of these vessels.
If you have ever cut a baby's umbilical cord, you have probably seen the thick, clear jelly that can ooze out of the cord when it's cut. When your baby's umbilical cord stump dries, the Wharton's jelly often appears yellow or green. This is normal, but this is one of the most common calls we get from postpartum families when they see the yellow or green color in the cord stump!
When the Wharton's jelly is doing its job, a true knot (or a cord around the baby's neck) is not usually a problem. Even as the knot is pulled, the jelly prevents it from being pulled tightly enough to restrict blood flow and compression of the blood vessels.
To learn more about the umbilical cord, check out our website.
https://www.columbiabirthcenter.com/blog/beyond-the-baby-whats-so-amazing-about-pregnancy