Umbilical Cord Presentation

Umbilical cord presentation is the lying of the cord below the presenting part with the membranes still intact, found on ultrasound or vaginal examination before labour or in early labour. It often resolves, but it is the forerunner of cord prolapse if the membranes rupture. It matters because rupture of membranes with a cord presentation causes prolapse and fetal hypoxia within minutes.

• Risk factors: malpresentation (breech, transverse lie), polyhydramnios, preterm birth, long cord, low lying placenta, multiple pregnancy.
• Persisting cord presentation in labour is an indication for caesarean section.
• Most cord presentations at 28 weeks resolve by term.

Women have no symptoms, and the finding is made on ultrasound or on a vaginal examination that feels cord with a pulse below the intact membranes. The fetal heart may show variable decelerations.

• Pulsatile cord felt through the membranes.
• Often with an abnormal lie or high presenting part.
• Differential diagnosis: cord prolapse, vasa previa, placenta previa, funic presentation of nuchal cord, bulging membranes with limb.
• Complications: cord prolapse on rupture of membranes, cord compression, fetal hypoxia, fetal death, emergency caesarean section, preterm birth.

The approach is ultrasound with colour Doppler, and a vaginal examination is avoided unless cord presentation is suspected in labour.

• Transabdominal and transvaginal ultrasound with colour Doppler: cord vessels between the presenting part and the internal os, below the membranes.
• Presentation and lie, amniotic fluid index, placental site, cervical length, cervical dilatation.
• Cardiotocography for variable decelerations.
• Repeat the scan after position change and again in 1 week, because many resolve.

The principle is to avoid rupture of the membranes and to deliver by caesarean section if the cord stays below the presenting part at term or in labour.

• Supportive: avoid digital examination, amniotomy and external version; advise to attend at once for contractions or leaking fluid; admit when labour starts; cardiotocography on admission.
• Pharmacological: betamethasone 12 mg IM twice, 24 hours apart, between 24 and 34 weeks and 6 days if preterm delivery is likely; terbutaline 0.25 mg subcutaneous once for contractions while preparing for delivery; cefazolin 2 g IV before caesarean section; oxytocin 10 IU IM at birth.
• Procedures: repeat ultrasound weekly from 32 weeks; elective caesarean section at 37 to 38 weeks if the cord presentation persists; emergency caesarean section if labour starts, membranes rupture or the tracing becomes abnormal; if the cord resolves, plan birth by the presentation and monitor continuously in labour.
• Red flags: leaking fluid, contractions, palpable cord, bradycardia or variable decelerations, bleeding.
• Follow-up: weekly ultrasound and cardiotocography from 32 weeks; antenatal review weekly from 36 weeks; newborn Apgar score and examination.