Everything you need to know about umbilical cord

The umbilical cord is the connection between your baby and the placenta during pregnancy. It contains blood vessels that carry oxygen and nutrients to your baby and take waste products away. After birth, the cord is clamped and cut, leaving the small stump that later becomes your baby’s belly button.

For most pregnancies, the umbilical cord quietly does its job without you needing to think much about it. You may hear more about it during scans, birth planning or labour, especially if your maternity team discusses cord clamping or a cord-related complication.

What is the umbilical cord?

The umbilical cord connects your baby’s abdomen to the placenta inside the uterus.

According to RCOG, it contains blood vessels that carry blood rich in oxygen and nutrients to the baby and take waste products away. The placenta then allows exchange between your circulation and your baby’s circulation.

The cord develops during early pregnancy and grows alongside your baby. By the time of birth, it has provided the physical link between baby and placenta throughout pregnancy.

What is inside the umbilical cord?

A typical umbilical cord contains three blood vessels: one vein and two arteries.

The umbilical vein carries oxygenated, nutrient-rich blood from the placenta towards the baby. The two umbilical arteries carry blood containing waste products from the baby back towards the placenta.

These vessels are surrounded by protective connective tissue known as Wharton’s jelly. This helps cushion the vessels as the cord moves and bends.

Sometimes an umbilical cord has two vessels rather than three. If this is identified during an ultrasound, your maternity team can explain what it means for your individual pregnancy and whether any additional monitoring is recommended.

How does the umbilical cord connect to the placenta?

One end of the cord attaches to your baby at the abdomen. The other attaches to the placenta.

The placenta itself is attached to the wall of the uterus and acts as the exchange organ between you and your baby. Oxygen and nutrients pass across the placenta and enter the baby’s circulation through the umbilical cord.

Your blood and your baby’s blood do not simply flow directly into one another. The placenta allows substances to be exchanged between the two circulations.

Can the umbilical cord move?

The cord is surrounded by amniotic fluid and can move as your baby changes position.

This means its position is not necessarily fixed throughout pregnancy. RCOG notes that ultrasound cannot predict who will experience an umbilical cord prolapse because the baby and cord can change position.

You may also hear that the cord is around part of the baby’s body during an ultrasound. The significance of any finding depends on the circumstances, so your midwife or obstetrician is the right person to explain what has been seen.

What does it mean if the cord is around the baby’s neck?

A cord around the baby’s neck is commonly called a nuchal cord.

Finding this can sound alarming, but the clinical significance varies. A cord can move as the baby moves, and maternity professionals assess the baby’s wellbeing rather than relying on the cord’s position alone.

If a nuchal cord is identified on a scan or during labour, your maternity team can explain whether it changes anything about your care. Do not use information about cord position as a reason to ignore reduced or changed fetal movements.

What is umbilical cord prolapse?

Umbilical cord prolapse is an uncommon but serious complication. It happens when the cord slips down in front of the baby after the waters have broken and enters the vagina.

RCOG explains that the cord can then become compressed by the baby or by contractions. This can reduce blood flow through the cord and therefore reduce the baby’s oxygen supply.

Cord prolapse is more likely in some situations, including when the baby is breech or transverse, when the waters break before 37 completed weeks, with multiple pregnancy, or when there is more amniotic fluid than usual. Having a risk factor does not mean that cord prolapse will happen.

Because cord prolapse is an emergency, maternity teams act quickly if it occurs.

What should you do if you see or feel the cord?

If you can see or feel what may be the umbilical cord in your vagina after your waters have broken, RCOG advises calling 999 immediately and telling the ambulance service that you are pregnant and think you have a prolapsed cord.

Do not try to push the cord back inside or handle it.

RCOG advises getting into a knee-chest position while waiting for the ambulance, with your knees on the floor and your chest lowered forward. This is emergency guidance specifically for suspected cord prolapse.

If you are unsure what you are feeling but are worried after your waters have broken, contact your maternity unit urgently for advice.

What happens to the umbilical cord after birth?

After your baby is born, the umbilical cord is clamped and cut, separating your baby from the placenta.

The remaining cord stump attached to your baby’s abdomen dries and eventually falls away. Your maternity team will give you current advice about caring for the stump after birth.

The placenta is delivered separately during the third stage of labour.

What is delayed cord clamping?

Delayed, deferred or optimal cord clamping means waiting for a period after birth before clamping the umbilical cord.

NHS England describes optimal cord management as delaying clamping so that blood can continue to transfer from the placenta to the baby during the transition after birth. Current maternity practice supports delayed cord clamping for many babies, although the timing can depend on the circumstances surrounding the birth.

For babies born preterm, NHS England highlights important benefits from optimal cord management. Your maternity team can explain the approach they recommend for your baby.

There are situations where clinical circumstances may affect when the cord is clamped. Birth plans can therefore include preferences about cord clamping while allowing your maternity team to respond to what is happening at the time.

Who can cut the umbilical cord?

Once the cord is ready to be cut, it may be cut by a healthcare professional or, depending on the circumstances and local practice, by you or someone supporting you at the birth.

If this is something you have a preference about, you can mention it to your midwife and include it in your birth preferences.

The cord itself does not contain nerves in the way skin does, so cutting it does not cause the baby pain.

What happens if there is a problem with the cord?

Umbilical cord findings can mean very different things. Some are simply observations during a scan or birth, while others may need closer monitoring or urgent care.

Your maternity team may consider the baby’s growth, movements, heart rate, position, placental findings and other aspects of the pregnancy when deciding whether a cord finding matters clinically.

If something has been identified on an ultrasound report, ask your midwife or obstetrician what the exact finding means rather than trying to interpret the terminology alone.

When to get professional advice

Speak to your midwife or obstetrician if an ultrasound has identified an umbilical cord finding that you do not understand, or if you have questions about how a cord finding could affect your pregnancy or birth.

Contact your maternity unit promptly if your waters break, particularly if you have previously been told that your pregnancy has factors that increase the risk of cord prolapse. Follow the individual instructions your maternity team has given you.

If you see or feel the umbilical cord in your vagina after your waters have broken, call 999 immediately. RCOG advises not touching or attempting to push the cord back inside and recommends the knee-chest position while waiting for emergency help.

Contact your maternity unit immediately if your baby’s movements reduce, stop or change from their usual pattern. Do not rely on the position of the umbilical cord, a home Doppler or another explanation to dismiss a change in movements.

For urgent medical concerns where you cannot reach your maternity service, NHS 111 can advise you. Call 999 for a life-threatening emergency.