What causes the umbilical cord to wrap around a baby's neck?

The umbilical cord wraps around the baby's neck when they move through its loop. It is associated with a long second stage labor, inducing labor and fetal heart rate abnormalities.

In addition to wrapping around the neck, the umbilical cord can wrap around other parts of the body. It wraps around the neck once in about 20 percent of cases, and more than once in 5 percent of cases, as reported by Medscape. It is possible to detect the nuchal cord using a doppler ultrasound with 90 percent accuracy. In most cases, the nuchal cord does not warrant intervention and it rarely leads to fetal deaths. Although some studies reveal a slightly elevated pH as an effect, there are no clinical causes for concern.