True Knot, Hypoxic-Ischemic Encephalopathy (HIE), and Cerebral Palsy

“True knots” are knots that form in the baby’s umbilical cord, occurring in roughly one out of every 100 pregnancies. They happen most often in identical twins sharing the same amniotic sac. They can also occur when babies flip and turn in the womb. Because cord vessels compress when a knot tightens, these knots are very dangerous, increasing the chances of fetal death and brain injury from hypoxic-ischemic encephalopathy (HIE) significantly. Knots are detectable via ultrasound, however, and it is standard procedure to test for knots prenatally when certain risk factors exist. Failing to do so is medical negligence. Due to the high risks posed by these knots, it is common to admit the mother to the hospital for close monitoring to prevent sudden fetal distress. C-sections are often necessary in these cases.  

Video: True Knot

In this video, Reiter & Walsh ABC Law Centers’ in-house nurse Andrea Shea discusses what a true knot is and how they can cause hypoxia.

True Umbilical Cord Knot

A true knot in the umbilical cord is exactly what it sounds like: a knot that forms in the baby’s umbilical cord.  Knots occur in about one in every 100 pregnancies; in one of every 2,000 deliveries, the baby has a true knot that causes serious problems.  True knots happen most frequently in monoamniotic twins (identical twins that share the same amniotic sac).  Some knots arise as the baby flips and turns during pregnancy.  This is more likely to occur when relatively more amniotic fluid is surrounding the baby, as in early pregnancy and cases of polyhydramnios (an excess of amniotic fluid).

Knots are also associated with multiparity (having had two or more previous pregnancies), advanced maternal age, and long umbilical cords.  Due to the compression of the cord vessels when a knot tightens, true knots greatly increase the chances of fetal demise and hypoxic-ischemic encephalopathy (HIE).

Knots can be detected with ultrasound imaging.  When certain risk factors are present, such as the mother being pregnant with monoamniotic twins, it is the standard of care to test for knots prenatally.

A C-section delivery is often the safest way to deliver a baby when a true knot and fetal distress are present.

Risk Factors for a True Knot

A baby is at an increased risk of having a true knot if:

  • There is a long umbilical cord
  • There is an excess of amniotic fluid (polyhydramnios)
  • The mother is carrying monoamniotic twins
  • The mother is older (greater than 35 years of age)
  • The mother smokes or uses drugs
  • She is large for gestational age or macrosomic

** Researchers think that nutritional deficiencies that affect the structure and protective barrier of the cord can also put a baby at risk for a true knot.

Symptoms of a True Knot

Decreased fetal activity after week 37 is a common sign of a true knot.  An abnormal or non-reassuring fetal heart rate will occur when the knot is serious enough to cause a lack of oxygen to the baby’s brain.

Diagnosing a True Knot

Although an abnormal or non-reassuring heart tracing can be indicative of a true knot, an ultrasound examination is the method of choice for diagnosis of a knot.  Specifically, four-dimensional, color Doppler and power Doppler examination are the most important modalities for assessment and diagnosis of a true knot.

Treating an Umbilical Cord True Knot | HIE Prevention

When risk factors for a true knot are present, an ultrasound examination should be performed to determine if there is a knot.  Knots can form at any time, although they are more common in certain instances, such as when the cord is long, the baby is moving, or there are monoamniotic twins.  An ultrasound should be performed periodically during pregnancy, and when a baby has risk factors for a knot, more frequent ultrasounds are required.   When a true knot is diagnosed, strict monitoring of fetal well-being is required during pregnancy and delivery.  Often, the physician will admit the mother to the hospital for close and continuous monitoring.  True knots can tighten at any time, especially during delivery.  Diagnosis and close monitoring can help prevent sudden and unforeseen oxygen deprivation and distress in the baby.  Often, a baby must be delivered by cesarean section when a true knot is present, and if the baby is experiencing non-reassuring heart tones, an emergency C-section is usually necessary.

Legal Help for Children with HIE and Injuries from a True Knot

If your loved one suffered permanent damage from an umbilical cord complication, we encourage you to contact a law firm with experience in these types of complex cases. Reiter & Walsh, P.C. was established to focus exclusively on birth injury cases. Since the firm’s inception in 1997, our legal team has addressed the special needs of our clients in a variety of birth injury, pregnancy, and newborn medical malpractice cases. Our attorneys and in-house medical staff determine the causes of our clients’ injuries, the prognoses of birth-injured children, and areas of medical negligence. While we’re based in Detroit, Michigan, our attorneys handle cases all over the United States. We’ve handled birth injury cases in Michigan, Ohio, Washington D.C., Pennsylvania, Tennessee, Arkansas, Mississippi, Texas, Wisconsin, and more. Our birth injury team is also equipped to handle cases involving military medical malpractice and federally-funded clinics.

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