29 Jan What is a nuchal cord? Is it dangerous?
I am 34 weeks pregnant. I had a last trimester ultrasound scan recently and was told that my baby’s umbilical cord was wrapping round the neck. Is this a serious condition? Do I have to undergo Caesarean section? please advise.
A: The umbilical cord is a flexible tube-like structure that connects the developing baby to its mother. It is attached to the baby’s belly button (umbilicus) at one end and to the mother’s womb through the placenta at the other. It is the lifeline for the foetus as it carries oxygen and nutrients from the mother to the baby and transfers carbon dioxide and waste products in the opposite direction to the mother to be excreted.
The umbilical cord is formed around the fifth week of pregnancy and can grow up to 50cm long at birth. It is a tough, sinewy cord with a soft, gelatinous filling called “Wharton’s jelly”. This jelly is designed to support the blood vessels running in the cord and to prevent them from being compressed. It also keeps the cord from forming knots when the foetus moves or somersaults in the mother’s womb.
The foetus is constantly moving in the womb. These movements may cause the umbilical cord to wrap round the baby’s neck either once or multiple times. This condition is called the nuchal cord. It is present in about 25 to 40% of babies at birth.
As in your case, most parents are anxious to know whether the nuchal cord will compromise the oxygen supply to the foetus and should caesarean section be done for safe delivery. Amazingly, in most cases, the blood vessels in the cord are not compressed and the foetal well being is not affected. Normal delivery can be accomplished if the foetal heartbeat is properly monitored during labour.
Caesarean section is only indicated during labour if the cardiotocograph (CTG), an electronic means of monitoring foetal heart rate and uterine contractions, indicates that the baby is in distress.
In rare occasions- one in 2,000 births- the nuchal cord may form a “true knot”. This may pose certain risks during delivery. However, in the majority of cases, the cord would not tighten too much and normal delivery can still be achieved.