Long Umbilical Cord

A long umbilical cord is a cord longer than 70 cm at term. It results from increased fetal movement or large amniotic volume. It matters because it is linked with true knots, nuchal coils, entanglement, cord prolapse, thrombosis and stillbirth.

• Risk factors: polyhydramnios, male fetus, multiparity, fetal hyperactivity, maternal diabetes.
• Antenatal diagnosis is unreliable.
• Cord length is measured after birth.

Most women have no symptoms. Some have vigorous fetal movement, polyhydramnios or a tracing with variable decelerations in labour.

• Marked fetal movement.
• Large for dates uterus with polyhydramnios.
• Differential diagnosis: nuchal cord, true knot, cord prolapse, cord entanglement around the limbs, cord torsion.
• Complications: true knot, multiple nuchal coils, cord prolapse, cord compression, cord thrombosis, fetal distress, stillbirth, neonatal asphyxia.

The approach is ultrasound with colour Doppler to find knots and coils, and cord length is measured at birth.

• Ultrasound: long cord with redundant loops, coils around the neck or limbs on colour Doppler, polyhydramnios; true knot shows a "hanging noose" sign.
• Cardiotocography for repeated variable decelerations.
• Measure the cord after birth; length above 70 cm confirms the diagnosis.
• Glucose tolerance test if polyhydramnios is found.

The principle is surveillance of fetal movements and heart rate, readiness for cord prolapse, and delivery planned on obstetric grounds.

• Supportive: daily fetal movement counts; teach to attend at once for reduced movements; birth in a facility with continuous cardiotocography and caesarean section.
• Pharmacological: oxytocin 10 IU IM at birth; terbutaline 0.25 mg subcutaneous once for cord prolapse while preparing for delivery; metformin 500 mg oral with meals increased to 1 g 12-hourly (maximum 2.5 g daily) or insulin for diabetes; cefazolin 2 g IV before caesarean section.
• Procedures: continuous cardiotocography in labour; controlled amniotomy with the head engaged and a check for cord afterwards; caesarean section for abnormal tracing or cord prolapse; delivery at 39 to 40 weeks for no other indication.
• Special groups: women with diabetes and a long cord with polyhydramnios have delivery at 38 to 39 weeks with glucose controlled by insulin infusion of 1 to 2 units per hour for glucose above 7 mmol/L.
• Red flags: reduced fetal movements, variable or prolonged decelerations, cord felt in the vagina, bradycardia.
• Follow-up: newborn examination for cord marks and anaemia; placental and cord histology if there was a knot or stillbirth.