Umbilical Cord Knots: Causes, Signs and Treatment

The umbilical cord is structure that resembles a tube which forms a connection between your baby and you during pregnancy. Its formation begins at around fourth week of pregnancy. It generally grows to become around 22 inches in length. There are multiple conditions of umbilical cord including the cord is either too short or too long, it’s not connected well to placenta or it’s got squeezed or knotted. Problems during labor, pregnancy and birth may occur due to these conditions. The article discusses knot in umbilical cord.

Two Types of Knots in Umbilical Cord

False Knots (Pseudoknots)

Any protuberance or bulge in the umbilical cord of a baby present in an ultrasound is very likely a false knot. These types of knots are slight variation in anatomy of the cord, generally formed by blood vessel swelling or when the cord is covered by excessive Wharton’s jelly.

It is relatively common to have small pseudoknots during pregnancies. A physician cannot untangle these knots as these are formed inside the umbilical cord and not outside the cord; however, fortunately, there is no clinical significance of these knots and they do not pose any danger to the health of the baby.

True Knots

As the name suggests, a true knot is formed when the cord interweaves or loops around itself. These knots may form during pregnancy (the baby is active during pregnancy and moves in amniotic fluid) and during delivery. As per definition, true knots may be untangled manually as they are formed by knotting of the umbilical cord on its outside.

A true knot in umbilical cord may be present in less than two percent of pregnancies. Majority of them are loose knots and don’t result in a problem.

But in case the umbilical cord of your baby gets a true knot early on during pregnancy, the future movements and growth of the baby may tighten the knot and squeeze off oxygen and blood supply to your baby. True umbilical knots become more dangerous the nearer your baby reaches to birth. In worse scenarios, it may cause asphyxia resulting in brain damage and death. The mortality rate of tight knots is 10%.

True Knots in Umbilical Cord: Cause, Signs and Treatment

How Does a Knot Form in Umbilical Cord?

During early pregnancy, the baby can move freely in the womb. As they do so, they may drag and loop the umbilical cord and form a knot. According to physicians, majority of true umbilical cord knots get formed between ninth and 12th week of pregnancy and quite strangely during labor. Below are mentioned some factors which seem to result in the formation of a true knot in umbilical cord:

  • Male baby
  • Active baby
  • Small baby
  • Older mother
  • Excessive quantity of amniotic fluid
  • Long cord (umbilical)
  • Second pregnancy (or subsequent pregnancies)
  • Multiple babies present in the uterus

During labor, true knots get formed or are tightened as there is movement of the baby to get positioned for delivery. Physicians should proactively notice any signs and symptoms of fetal distress (or fetal status that is non-reassuring) as that indicates a tight true umbilical cord knot.

Symptoms of Umbilical Cord Knot

One of the most common signs of an umbilical cord knot is reduced activity of the fetus post 37th week of pregnancy. In case the umbilical cord knot happens during labor, an abnormal fetal heart rate will be detected by the fetal monitor.

How Is the Diagnosis Made of True Knot in Umbilical Cord?

The following may be done to diagnose a true knot of cord:

  • Color Doppler ultrasonography
  • Routine abdominal ultrasound exam of the pregnant female
  • Examination of umbilical cord and placenta during delivery

Should You Show Concern?

A substance referred to as Wharton’s jelly cushions the important arteries and blood vessels of umbilical cord and provides protection to them even if it gets a knot. This implies that the situation will not get worse and a true knot that becomes tight will not happen. Till the time the knot is loose, it will not cause any harm to the baby.

However, in case the knot gets tight, the blood circulation from the mother to the fetus will get interfered and the fetus will get deprived of oxygen. Your baby is more prone to develop this type of complication during their descent through birth canal; however, such cases are very rare.

What You Should Do?

Nothing can be done to prevent the formation of a knot in umbilical cord. However, you should keep an eye on the general health of your baby, particularly in the later part of your pregnancy. This can be done by performing regular counts of kicks and informing your physician in case there are any changes in the activity of your fetus.

If during delivery, there is tightening of a loose umbilical cord knot, your physician will detect your baby’s reduced heart rate and they will take appropriate steps to make sure that your baby enters safely into this world. Usually the best decision in such cases is to perform an immediate cesarean section and deliver the baby.