Definition
The umbilical cord knot is a dreaded complication during pregnancy and delivery. Increased fetal movement in the womb can cause the umbilical cord to twist or even knot. In the umbilical cord blood vessels run from the mother to the child and back again.
This supplies the child with oxygen and nutrients from the mother and removes metabolic products from the child via the mother’s blood. The umbilical cord has a spiral structure to prevent the blood vessels from kinking. In most cases, umbilical cord nodes are only loosely wound, which does not affect the blood flow.
If there is a continuous strong pull on the umbilical cord, as is the case at birth, the knot can pull and thus severely restrict or completely interrupt the supply to the child. In the worst case, an umbilical cord knot leads to the death of the child in the womb. A symptomatic (=pulled) umbilical cord node is an absolute emergency and an emergency C-section must be performed immediately.
How often is there an umbilical cord knot?
The umbilical cord node is a very dreaded complication in obstetrics. A distinction is made between a simple wrap, which occurs in 20% of all births and usually causes no complications, and a multiple wrap of the umbilical cord, which occurs in < 1% of births, where the risk of complications is significantly increased. A real umbilical cord knot is found in 1-2% of all births. This occurs when the baby slips through a loop in the umbilical cord during the movements it makes.
Causes
An umbilical cord knot is usually caused by strong infantile movements in the womb. In addition, the amount of amniotic fluid plays a major role. At the end of pregnancy, 800-1500ml of amniotic fluid should surround the child.
If the amount of amniotic fluid is over 2000ml, it is called a polyhydramnion (amniotic fluid addiction). The child has more room to move and rotate around the umbilical cord, which can lead to knotting. Another risk factor is a longer umbilical cord, which has more room to move and the child can even wrap itself around it several times.
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