Too long or too short, knotted or tangled ― umbilical cord issues can have a serious impact on your pregnancy.


When Gwendoline Heng was 35 weeks pregnant, her gynaecologist noticed something slightly alarming during an ultrasound.

“My baby’s umbilical cord seemed to be loosely looped around his neck. It wasn’t of immediate concern, but my doctor said it had to be monitored closely,” she recalls.

The umbilical cord, which connects a baby in the womb to its mother, runs from an opening in your baby's stomach to the placenta in the womb.

To play it safe, her doctor recommended that her baby be induced at 37 weeks ― at full term ― but before the baby got too big. “I think the concern was that if the baby was too big, it could lead to [umbilical] cord compression during delivery,” says Heng, who wanted a vaginal delivery.

Heng’s condition is known as a nuchal cord, one of several umbilical cord conditions that can occur during pregnancy. Umbilical cord compression obstructs the flow of blood.

While Heng’s baby was delivered safely, umbilical cord issues can be critical, as it’s the baby’s source of oxygen and nutrition. The tube-like structure also helps to remove foetal waste, and carries the baby’s blood back and forth between the baby and the placenta.

Here are several umbilical cord conditions that could affect your baby’s health.

1. Nuchal cord

A nuchal cord happens when the umbilical cord is wrapped around the foetus’ neck ― a single loop happens in about 25 per cent of pregnancies. In fact, many babies are born with a single loop without any complications

“For the most part, a nuchal cord comprising a single loose loop around the neck is not dangerous,” says Dr Pamela Tan, a Thomson Medical gynaecologist and obstetrician. “If foetal growth, foetal movements and amniotic fluid is normal, then it’s a case of watchful waiting.

But she points out that “if the loop tightens significantly during labour, or when the baby descends into the pelvis, it is similar to the effect of strangulation”. The obstruction in the blood flow is usually reflected in CTG decelerations, or heartrate abnormalities. The baby may also pass meconium when this occurs, so an emergency Caesarean is performed when the ob-gyn observes these signs. 

If the loop tightens significantly during labour, or when the baby descends into the pelvis, it is similar to the effect of strangulation.”

Other more uncommon complications can include:

  • The formation of a true knot, leading to a still birth.
  • Intrauterine growth restriction if the cord is tight or has multiple loops.
  • Decreased foetal movements due to decreased blood circulation and oxygen deprivation.
  • Unusual physical features at birth, like dusky or blue skin, petechiae (red patches as a result of bleeding under the skin).

More rarely, a double or multiple looped nuchal cord may occur (less than 2.5 per cent), says Dr Tan.

“This is associated with a higher likelihood of complications, as the likelihood of strangulation increases.” In these cases, the doctor may discuss with the patient about the possible risks and discuss options for an elective C-section.

2. Umbilical cord knots

When a knot forms in the umbilical cord, the vessels in the cord can become compressed, which can limit oxygen to the baby.

While true knots are rare (2 per cent or less), it can happen when the baby moves around in the womb.

Risk factors include high amniotic fluid, a high number of previous pregnancies, small foetuses, a long cord, or multiple pregnancies, Dr Tan notes.

It’s very difficult to diagnose a true knot on the ultrasound, she says. “There isn’t a specific ultrasound image and it’s hard to scan the entire length of the cord, especially as the fetus gets larger in the 3rd trimester.”

In the majority of the cases, the first signs are reduced foetal movements. This is why patients are always advised to be vigilant and return immediately should their foetal movements suddenly decrease, Dr Tan adds.


Baby with umbilical cord

3. Umbilical cord prolapse

This happens when the umbilical cord descends into the birth canal during labour ― before the baby does.

When this happens, the foetus can put stress on the cord, leading to a loss of oxygen and even a still birth.

The most common cause of umbilical cord prolapse is the premature rupture of membranes ― also known as when your water breaks.

Other risk factors include:

The gynae may notice signs of an umbilical cord prolapse, or feel the cord before the baby is delivered. Once a prolapse is diagnosed, the baby needs to be delivered immediately. The doctor may try to relieve pressure on the cord by moving the baby away. When this doesn’t work, an emergency C-section Is usually needed.

Babies only have a small amount of blood in their bodies so they don’t need to lose much to become very unwell or even die.

4. Vasa Previa

Vasa previa is the condition where some foetal umbilical cord blood vessels travelling from your baby to your placenta run very close to, or pass the cervix. These blood vessels are very delicate and can tear when you are in labour or when your waters break, Dr Tan explains.

This is very dangerous as the blood that is lost comes from your baby. Babies only have a small amount of blood in their bodies, so they don’t need to lose much to become very unwell or even die,” Dr Tan explains.

The condition is very rare, and affects between 1 in 1,200 and 1 in 5,000 pregnancies. But if this happens, up to 60 per cent of affected babies die.

Often, vasa previa has no symptoms, so this condition can go undetected until labour, when the baby is already in distress, or it is only discovered when there’s a still birth.

Signs of vasa previa include painless vaginal bleeding, especially if the blood is a very dark red ― as the baby’s blood is naturally lower in oxygen than the mum, which makes it darker in colour.

“If your doctor suspects that you may have vasa previa when you go into labour or when your water breaks, usually an emergency C-section would be recommended,” Dr Tan notes.

If you are diagnosed with the condition before you go into labour, you may be offered a planned Caesarean at around 34 to 36 weeks of pregnancy.

Dr Tan explains, “As this would mean that your baby will be born preterm, you would be offered a course of steroids to help mature your baby’s lungs and other organs.”

Photos: iStock

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