Prevalence:

• 1 in 100 pregnancies.

Ultrasound diagnosis:

• Visualisation of a transverse section of the umbilical cord surrounded by a loop of umbilical cord: ‘hanging noose sign’.
• Predisposing factors include: long cord, small fetus, polyhydramnios, monoamniotic twins.

Investigations:

• Detailed ultrasound examination.
• Routine surveillance of the umbilical cord for knots may not be justifiable because it is time consuming and of uncertain sensitivity or benefit.

Follow up:

• The detection of an umbilical cord knot is not an indication for delivery unless associated with evidence of fetal compromise, such as abnormal fetal heart rate pattern.
• Closer fetal surveillance by fetal Dopplers and cardiotocography should be considered.

Prognosis:

• Risk of stillbirth is increased by 5 times.

Recurrence risk:

• No increased risk of recurrence.