When the umbilical cord encircles a baby’s neck, this occurrence is medically termed a nuchal cord (ICD-10-CM: O69.1). A nuchal cord can develop during pregnancy, labor, or birth. This is a relatively common situation, and it rarely leads to complications for the baby.
What is a Nuchal Cord?
A nuchal cord occurs when the umbilical cord wraps one or more times around the fetus’s neck. This is a frequent finding, with studies indicating it is present in approximately 10% to 29% of fetuses, and up to 25% of babies are born with a single loop around their neck. The incidence can increase with advancing gestational age.
Healthcare providers classify nuchal cords based on the number of loops and their tightness. There can be a single loop or multiple loops, and the cord can be described as loose or tight. A loose nuchal cord may even spontaneously undo itself with fetal movement, while a tight nuchal cord is less likely to unwind naturally. These entanglements usually happen randomly due to natural reasons, such as the baby’s active movements within the womb. An umbilical cord that is longer than average, typically over 27 to 32 inches, or an excessive amount of amniotic fluid, which allows for more fetal movement, can also contribute to the formation of a nuchal cord.
Identifying a Nuchal Cord
A nuchal cord can sometimes be identified during routine prenatal ultrasounds. While a healthcare provider might observe the cord around the neck, they often do not report this finding to parents because it is common and typically does not present a concern unless blood flow is compromised. Doppler ultrasound can be used to assess proper blood flow through the umbilical cord.
During labor and delivery, a nuchal cord is frequently discovered when the healthcare provider feels the cord around the baby’s neck as the head emerges from the birth canal. Another indicator can be changes in the fetal heart rate pattern during monitoring. Variable decelerations, which are temporary drops in the baby’s heart rate, can suggest compression of the umbilical cord vessels.
Management During Labor and Delivery
When a nuchal cord is present during labor and delivery, continuous monitoring of the baby’s heart rate is standard practice to detect any signs of distress. If the cord is loose, the provider can often gently slip it over the baby’s head once it emerges.
If the nuchal cord is too tight to slip over the head, or if there are multiple loops, a “somersault maneuver” may be employed. This technique involves guiding the baby’s head close to the birthing person’s thigh, allowing the baby’s body to somersault through the cord loop, which helps to deliver the baby with the cord intact. This approach aims to minimize pressure on the cord and facilitate delayed cord clamping. In some situations, if the somersault maneuver is not feasible or if there are signs of fetal distress, the cord might need to be clamped and cut before the rest of the baby’s body is delivered. In rare instances where there is persistent fetal distress that cannot be resolved, an emergency C-section may be performed.
Impact on Baby and Long-Term Outlook
For the vast majority of cases, a nuchal cord does not cause any lasting harm or complications for the baby. Most babies born with a nuchal cord experience a normal delivery and do not have increased risks of low Apgar scores or developmental problems. The umbilical cord contains a protective substance called Wharton’s jelly, which helps to cushion the blood vessels and prevent compression.
In very rare instances, if the cord is tightly compressed for an extended period, it could potentially lead to temporary oxygen deprivation or reduced blood flow to the baby. Such situations might be indicated by changes in the baby’s heart rate during labor.