A true knot in the umbilical cord is a rare complication of pregnancy or childbirth. Typically, there are no symptoms, and most people are unaware of a knot in their umbilical cord. In most cases, your baby will be born healthy. But complications such as brain damage or stillbirth are possible.
What are umbilical cord knots?
Umbilical cord knots are similar to shoelace knots. Just as a shoelace can get tangled, so can the umbilical cord. Small nodules usually do not pose a risk to the fetus and often resolve independently. They occur naturally from the movement of the fetus around. A gel-like substance called Wharton’s jelly prevents small nodules from hardening.
But, sometimes, this knot becomes very tight, and healthcare providers call this a true knot. Unlike a small knot that is easy to loosen, a true knot is so tight that it can block oxygen and nutrients from reaching the fetus. It can cause complications during pregnancy and childbirth because it deprives the fetus of these vital substances.
True nodules are rare and usually do not cause pregnancy complications. In most cases, the baby is born healthy.
How common are umbilical cord knots?
Umbilical cord knots are rare, occurring in only 0.3% to 1.2% of pregnancies. This means that for every 100 pregnant people, only 1-3 might have a true knot in their baby’s cord.
It’s important to remember that not all knots are the same. There are two types:
- True knots: These are the rarer ones, forming a true knot like you’d see in a string.
- False knots are more common, just kinks or bulges in the cord, posing no risk to the baby.
While most true knots are harmless, you must ask your doctor for pregnancy-related concerns or questions. They can help you understand the risks, monitor your baby’s health, and guide you through any necessary precautions.
Why do umbilical cord knots happen?
The exact reason why umbilical cord knots happen isn’t fully understood, but there are two main explanations:
- Fetal movement: Early in pregnancy, when there’s more amniotic fluid and the baby has more space to move, the fetus’s movements can accidentally knot the cord. While most knots loosen independently due to the cord’s jelly-like substance (Wharton’s jelly), a true knot occasionally forms.
- Other risk factors: Certain factors are associated with a higher chance of umbilical cord knots, including:
- Long umbilical cord: This provides more length for the cord to tangle.
- Multiple fetuses: Twins or triplets have more cords that can intertwine.
- Low amniotic fluid means less space for the baby to move freely, potentially increasing the chance of the cord getting tangled.
- Maternal age and history: Advanced maternal age and previous pregnancies, particularly with a true knot, maybe slightly associated with increased risk.
It’s important to remember that having any of these risk factors doesn’t guarantee a knot will form, and most pregnancies with knots proceed without complications.
Ultimately, the cause of a true knot remains a complex interplay of fetal movement, cord characteristics, and potential contributing factors.
Who is at risk for umbilical cord knots?
Some umbilical cord knots occur naturally and may not have any known risk factors. But the following factors may increase the chances of developing a true knot:
- The fetus is small for its gestational age
- The umbilical cord is very long
- Identical twins (identical twins who share the same amniotic sac)
- Excessive amniotic fluid (polyhydramnios)
- Multiple pregnancies
- Age older than 35 years
- The feeling of low fetal movement
What are the complications of a true knot in the umbilical cord?
While most true knots in the umbilical cord don’t cause any complications, some can impact the baby’s health due to restricted blood flow.
Reduced Oxygen and Nutrients
A tight knot can compress the blood vessels in the cord, limiting the oxygen and nutrients reaching the baby. This can lead to:
- Slow growth: Intrauterine growth restriction (IUGR) if the knot restricts vital resources for development.
- Reduced fetal movement: The baby may move less due to lack of oxygen, potentially raising concerns.
- Low birth weight: Restricted nutrients can make the baby smaller than expected for their gestational age.
Rare but Serious Complications
- Stillbirth: In very rare cases, a very tight knot can completely cut off the baby’s oxygen supply, leading to stillbirth.
- Brain damage: Oxygen deprivation can cause damage to the developing brain, though long-term studies indicate most cases recover well.
Factors Influencing Severity
- Knot tightness: Tighter knots pose a greater risk of complications.
- Baby’s health: Underlying issues like prematurity or IUGR increase the vulnerability to cord knot impacts.
- Maternal conditions: High blood pressure or diabetes in the mother may slightly increase the risk.
Most true knots cause no problems, and babies are born healthy. Regular prenatal care and monitoring are crucial for early detection and intervention if needed.
Talk to your doctor for expert guidance and reassurance if you have concerns.
I hope this clarifies the potential complications of true knots and emphasizes the importance of prenatal care and open communication with your healthcare provider.
How do you know if you have an actual knot in the umbilical cord?
You often don’t know you have an actual lump until you give birth. However, some people notice less mobility in the third trimester, which can be a risk factor for a true knot. This is why it’s essential to let your doctor know if you don’t feel your baby moving.
Antenatal care providers can detect a true nodule by ultrasound during pregnancy after observing a decreased heart rate or fetal movement patterns. However, seeing a true nodule on a prenatal ultrasound is difficult, so the diagnosis is often made after the baby is born.
Sometimes, when a fetal heart rate changes, a doctor will detect a true nodule during labor and delivery. In these cases, the provider must act quickly and decide whether natural delivery is safe.
Treatment
Unfortunately, there is no direct treatment for a true knot in the umbilical cord. Once a knot forms, it cannot be physically undone or altered. However, your doctor can take steps to monitor the situation and address any potential complications.
Monitoring
- More frequent ultrasounds: These can help assess the knot’s tightness, blood flow in the cord, and the baby’s growth and activity.
- Fetal heart rate monitoring: This checks for changes in the baby’s heart rate, which can indicate potential distress.
- Biophysical profile: This combines ultrasound and fetal heart rate monitoring to assess the baby’s overall well-being.
Management
- Early delivery: If the knot appears very tight, restricts blood flow, or the baby shows signs of distress, your doctor may recommend early delivery by cesarean section to ensure the baby’s safety.
- Delivery plan: Depending on the situation, your doctor will develop a personalized delivery plan considering other risk factors and your preferences.
Remember
Most true knots do not cause problems; many babies are born healthy despite having one. Early detection and monitoring are crucial to identify potential complications and take necessary actions.
Regular communication with your doctor is essential to address your concerns and understand your case’s risks and management plan.
While there’s no direct treatment for the knot itself, focusing on monitoring, potential early delivery, and a personalized management plan can ensure you receive the best possible care and maximize the chances of a healthy outcome.
The bottom line
Indeed, all pregnant women are worried about problems such as umbilical cord knots during pregnancy. Mothers always try to prevent such problems from happening to their children.
Although the thought of an actual knot in the umbilical cord may seem scary, these abnormalities are not very common, and when they do occur, they are usually not life-threatening. Most umbilical cords are not detected until after your baby is born.
It’s also important to remember that if an actual knot occurs, you do nothing to create it. There is also nothing you can do to prevent it from forming.
Instead of worrying about the possibility of an actual knot, focus on taking care of yourself and paying attention to your baby’s movements and kick count. If you have more concerns or worries about your baby’s development, call your OB/GYN.
Dr. Arjang Naim is one of the best ob-gyns in Los Angeles that you can visit.
References
https://my.clevelandclinic.org/health/articles/24964-true-knot-in-umbilical-cord
https://www.abclawcenters.com/umbilical-cord-problems/true-knot/
https://www.webmd.com/baby/what-to-know-about-umbilical-cord-knots
https://www.verywellfamily.com/true-knot-in-umbilical-cord-6891644
https://www.whattoexpect.com/pregnancy/pregnancy-health/complications/cord-knots.aspx