A nuchal cord happens when your baby’s umbilical cord becomes wrapped around their neck in the womb. Nuchal cords are quite common, and while they often do not cause any health problems, in rare cases, serious complications can occur.
Here is what you need to know about nuchal cords, their potential risks, and how doctors treat them.
What Is a Nuchal Cord?
The umbilical cord is responsible for delivering the oxygen and nutrients your baby needs to grow, as well as for carrying away waste. It’s a flexible tube that contains two arteries and one vein and is coated in a substance called Wharton’s jelly, which helps to protect the blood vessels inside.
If your baby’s umbilical cord gets wrapped around the baby’s neck one or more times, it is called a nuchal cord. The loops can be either loose or tight. Nuchal cords are grouped into types A and B.
Type A nuchal cords (also called unlocked cords) are free-moving and may come undone naturally. Type B nuchal cords (or locked chords) are wrapped in a way that does not allow them to come undone naturally, except for very rare cases.
What Causes a Nuchal Cord?
The fetal movements your baby makes before they are born is the most common cause of nuchal cords. An extra amount of amniotic fluid, allowing your baby to move around more freely, as well as a longer than average umbilical cord, might also cause your baby to have a nuchal cord.
Are There Risks of a Nuchal Cord?
Nuchal cords happen randomly and are very common. Research suggests they happen in more than one in four births. Type B nuchal cords are less common, with about 2% to 8% of babies born with one.
Research has shown that the longer your baby stays in your womb, the greater chance there might be for them to be born with their umbilical cord wrapped around their neck. Nuchal cords have been reported in 6% of babies at 20 weeks gestation, but that number increased to 29% at 42 weeks. Male babies are also more commonly born with nuchal cords than female babies.
Race and maternal age do not affect the chances of a baby having a nuchal cord. Labor also does not typically play a role. If your baby doesn’t have a nuchal cord before you go into labor, they are very unlikely to have one at birth.
Are There Complications of a Nuchal Cord?
While most nuchal cords do not cause babies any harm, some potential complications include:
- Umbilical cord knots
- Developmental delays
- Decreased amounts of amniotic fluid
- Decreased fetal movement
- Longer gestation periodS
- Intrauterine growth restriction (IUGR)
- Anemia
- Low levels of circulating blood (hypovolemia)
- High levels of blood acid (metabolic acidosis)
- Stillbirth
Sometimes the nuchal cord can wrap tightly around your baby’s neck and cause complications. This can lead to a condition called tCAN (tight cord around neck) syndrome. Symptoms of tCAN syndrome are similar to strangulation and include blood spots (petechiae) on the neck, face, and in the eyes; skin abrasions on the neck where the cord was wrapped; and dusky, purple colored skin on the face.
How Is a Nuchal Cord Diagnosed?
Nuchal cords can sometimes be seen during prenatal ultrasounds, but they are often first found at birth. Nuchal cords happen often, so it’s common for doctors to routinely check for one during delivery.
Is There Treatment for a Nuchal Cord?
There are currently no nuchal cord treatment options before your baby is born. If your baby's nuchal cord is diagnosed before birth, you will likely have extra monitoring during labor to make sure your baby's heart rate is normal.
During birth, nuchal cords are normally loose enough for your doctor to loop the cord back around the baby’s head and free their neck. If the cord is too tight to slip over your baby’s head, it might be clamped and cut before your baby is completely delivered to prevent it from tearing away from the placenta.
If your baby’s heart rate declines during labor because of a nuchal cord, your doctor might have you change positions to relieve any extra pressure put on the umbilical cord, and give you extra fluids or oxygen. If your baby’s heart rate doesn’t improve, you may be given medication to slow down your contractions or have a cesarean section.
Should I Worry If My Baby Has a Nuchal Cord?
Nuchal cords are very common and rarely cause any lasting complications or harm to your baby. Babies born with nuchal cords typically don’t have any increased risk of low Apgar scores, growth and developmental problems, or stillbirth. Be sure to talk with your doctor if you have any questions or concerns about nuchal cords during pregnancy or delivery.
