A loop of umbilical cord around the fetal neck (nuchal cord) is a common finding at delivery. Although available data are of low quality, the bulk of evidence suggests that nuchal cords are not associated with a statistically significant increase in the rate of any clinically important adverse fetal/neonatal event. In case reports and small case series, however, nuchal cords have been associated with adverse outcomes [1-3].
The term nuchal cord describes an umbilical cord that passes 360 degrees around the fetal neck. Nuchal cords can be classified as :
●Type A – A nuchal loop 360 degrees around the fetal neck where the placental end crosses over the umbilical end, entangling the neck in an unlocked pattern that can undo itself.
●Type B – A nuchal loop 360 degrees around the fetal neck where the placental end crosses under the umbilical end, entangling the neck in a locked pattern that cannot undo itself. This pattern can form a true knot when it passes down over the fetal body.
Nuchal cords can occur as single or multiple entanglements around the fetal neck. They may be loose or mildly to severely constricting. Disruption of the smooth contour of the fetal neck compressing the skin in that area, referred to as the "divot sign" , has been used to define tight nuchal cords .