When the umbilical cord poses a threat to the baby

The umbilical cord is a literal lifeline between mother and child. It is responsible for transporting oxygen-rich blood and vital nutrients to the foetus, while whisking away waste products. However, physical positioning of the cord can occasionally create clinical challenges. This is because the cord is a flexible, floating structure within the amniotic sac.

Can the cord become a threat?

When you hear about the cord becoming a ‘threat’, this is generally in reference to instances where this flow of life-sustaining resources is constricted or interrupted. The thought of cord issues can be frightening for expectant parents. It is important to understand how and why these complications occur.

A very common complication is called ‘nuchal cord’. It occurs when the cord wraps around the baby’s neck. In most cases, the cord is loose enough that it does not pose any danger and simply slips over the baby’s head during birth. It can be seen in about 25% to 30% of full-term deliveries.

Another common issue involves umbilical cord compression. The cord can be compressed when it becomes trapped between the baby and the uterine wall or during intense labour contractions. This results in the cord experiencing a temporary blood flow reduction, leading to decreased oxygen delivery to the baby. The risk of cord compression increases during low amniotic fluid conditions as this decreases the protective cushioning that surrounds the cord. Foetal distress can develop when this condition occurs repeatedly and lasts for extended periods, and so, it is crucial to manage it early.

A much rarer occurrence is ‘cord prolapse’, where the cord drops into the cervix ahead of the baby after the water breaks. This becomes a medical emergency, as, when the baby moves into the birth canal, they can compress the cord against the pelvis, which can result in cutting off of their own oxygen supply.

Sometimes, when a baby is moving and flips in the womb, they can swim through a loop in the cord, creating a knot. While most knots stay loose, a condition known as ‘true knot’ can tighten and restrict circulation. The length and structure of the cord also matter. Very long cords can increase the risk of knots.

What parents should know

Cord loops are fairly common and often resolve by themselves, and so, they are not generally screened for during routine ultrasounds. If any cord issues are detected during labour, simply changing the mother’s position is enough in most of the cases to shift the baby and relieve the pressure on the cord. Continuous foetal heart rate monitoring helps identify early signs of distress, allowing for timely action.

While the umbilical cord can present risks, it is a remarkably resilient, life-sustaining structure, forming the first and most significant link between mother and baby.

(Dr. Deepika Alva is consultant- obstetrician and gynaecologist, Motherhood Hospitals, HRBR Layout, Bengaluru. deepikaalva@gmail.com; Dr. Meghana Reddy Jetty is senior consultant – obstetrics, gynaecology, laparoscopy and aesthetic gynaecology, Aster Whitfield Hospital, Bengaluru. dr.meghanajetty@gmail.com)