Introduction
A true knot in the umbilical cord is an uncommon issue during pregnancy or childbirth. Generally, there are no noticeable symptoms, and many individuals may not realize that a knot has formed in the umbilical cord. In the majority of instances, babies are born healthy. However, there is a risk of complications such as brain damage or stillbirth.
What Is a True Knot in Umbilical Cords?
A true knot in the umbilical cord is comparable to that in shoelaces. Much like shoelace knots, the umbilical cord can also develop knots. Minor knots typically do not pose a risk to the developing baby and often unravel independently. These knots occur naturally as the fetus moves around, and a substance known as Wharton's jelly prevents them from tightening.
However, there are cases when a knot becomes very tight, known as a true knot. Unlike smaller knots that can easily loosen, a true knot is tight enough to restrict the flow of oxygen and nutrients to the developing baby. This can lead to complications during pregnancy and delivery as it deprives the fetus of these essential substances. Although true knots are rare and generally do not cause complications during pregnancy, they can be concerning. In most cases, babies born with true knots in the umbilical cord are stillborn healthy.
What Is the Umbilical Cord?
The umbilical cord is a crucial link between the placenta and the developing fetus. It serves as a vital vessel for transporting oxygen and nutrients from the placenta to the fetus, while also facilitating the transfer of waste from the fetus back to the placenta.
How Frequent Is a True Knot in the Umbilical Cord?
Approximately one in 100 pregnancies experience some form of knot in the umbilical cord. Not all knots are classified as "true" knots, with true knots occurring in less than one percent of all pregnancies.
What Causes Umbilical Cord Knots?
Healthcare providers caring for pregnant individuals cannot pinpoint the exact cause of umbilical cord knots. However, they are aware of factors that increase the risk of a true knot and recognize certain signs. Some knots occur naturally due to fetal movements, and the pressure from the process of labor and delivery can further tighten a knot.
Small knots typically do not raise concerns, but if a knot tightens into a true knot, it can potentially lead to complications. This is because the tight compression of the umbilical cord deprives the fetus of oxygen.
Doctors closely monitor for signs of a true knot, especially when identified risk factors exist. Importantly, it is crucial to understand that the formation of a knot is not caused nor a result of any actions.
What Occurs When There Is a Knot in the Umbilical Cord?
A true knot in the umbilical cord can impede the flow of essential oxygen and nutrients the fetus requires for survival. Think of a true knot like a knot in a garden hose. Just as a knot restricts the free flow of water in the hose, a true knot in the umbilical cord limits the smooth passage of vital substances needed for the baby's well-being.
Who Is Prone to Umbilical Cord Knots?
While some umbilical cord knots occur naturally without identifiable risk factors, healthcare providers recognize that certain factors may heighten the likelihood of a true knot:
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The fetus is smaller than expected for its gestational age.
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The umbilical cord is exceptionally long.
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Carrying monoamniotic twins (identical twins sharing an amniotic sac).
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Presence of excessive amniotic fluid (polyhydramnios).
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Having had two or more pregnancies (multiparity).
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Age older than 35.
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Reduced fetal movements are noticed.
What Are the Complications of a True Knot in the Umbilical Cord?
True knots in the umbilical cord can lead to significant complications as they disrupt the fetus's oxygen supply. The lasting impact of a knot is influenced by its tightness. A tightly knotted cord could result in severe hypoxia, potentially proving fatal for the fetus. On the other hand, a less tight knot may cause mild hypoxia, leading to less severe and potentially reversible damage. Some enduring consequences of true knots in the umbilical cord include:
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Cerebral palsy.
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Hypoxic-ischemic encephalopathy (HIE).
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Developmental or cognitive delays.
How Can a True Knot in the Umbilical Cord Be Identified?
Typically, the presence of a true knot remains unknown until delivery. However, some individuals may observe reduced fetal movement during the third trimester, which can serve as a potential indicator of a true knot. Communicating any decrease in fetal movement to the healthcare provider is crucial. Healthcare professionals can diagnose a true knot through prenatal ultrasound, especially if there is a noted decline in the fetus's heart rate or movement patterns. Detecting a true knot on prenatal ultrasound, though, is challenging, making post-birth confirmation more common.
In some situations, a healthcare provider may identify a true knot during labor and delivery when there is a sudden alteration in the fetus's heart rate. In such cases, quick decision-making is essential for the provider to assess the safety of continuing with vaginal delivery.
What Actions Can Healthcare Providers Take for a True Knot in the Umbilical Cord?
Healthcare providers cannot untie or treat true knots. Effectively managing a true knot involves recognizing associated risk factors and monitoring for potential complications. If providers identify a knot on ultrasound before delivery, they will intensify monitoring during the third trimester. This may involve additional ultrasounds, Doppler studies, and fetal growth and movement assessments.
If providers discover a knot during an ultrasound before delivery, they will increase monitoring during the third trimester. This may include additional ultrasounds, Doppler studies, and fetal growth and movement assessments. In the event of detecting a knot during delivery, prompted by changes in fetal heart rate, it becomes crucial to monitor for signs of fetal distress closely. Contractions during childbirth can tighten the knot further, making it essential for the provider to observe the fetal heart rate as labor progresses closely. An emergency C-section may be necessary if signs of fetal distress or oxygen deprivation arise.
Although the situation can be concerning, true knots are rare and typically do not cause permanent harm if managed appropriately.
Conclusion
A true knot in the umbilical cord, though uncommon, can pose serious risks to fetal health by restricting the supply of oxygen and nutrients. The tightness of the knot plays a crucial role in determining the severity of potential complications. Identifying a true knot often occurs during delivery or through prenatal ultrasound, with intensified monitoring if risk factors are present. While complications such as cerebral palsy or developmental delays may arise, it is reassuring to note that true knots are rare, and appropriate management by healthcare providers can mitigate the risks and prevent long-term harm to the baby.
