When in the womb, your baby is connected to you through the umbilical cord and placenta. Oxygen, nutrients and essential blood supply reach the baby’s bloodstream through the umbilical cord, which normally has three blood vessels; two arteries and one vein. However, sometimes, there are abnormalities in the umbilical cord. They can be shorter than the normal or longer, and at times, there could be a two-vessel umbilical cord instead of a normal one. Understanding the abnormality that occurs in this important link between you and the baby can help you take steps to prevent or handle it efficiently. In this article, we shall talk about the two-vessel umbilical cord abnormality and also look into its possible causes, risks and diagnosis. But first, let’s understand what a normal umbilical cord is and what its functions are.
A normal umbilical cord will have two arteries and a vein forming a three-vessel cord. It is covered with Wharton’s Jelly, which is a gelatinous substance and is about 20 cms in length. The important functions of these blood vessels are as follows:
Now, let’s understand what a two-vessel umbilical cord is and the factors associated with this condition.
Sometimes during the development of the baby, an abnormality occurs, and only one artery and a vein are present. The umbilical cord is then called a two-vessel umbilical cord or single artery umbilical cord (SUA).
Less than 1% of single pregnancies and about 6-11% of multiple pregnancies have this condition. Although the exact cause is unknown, the condition could occur either due to the improper splitting of cells when forming the umbilical cord (around the 5th week of pregnancy) or due to improper formation of the second artery.
As explained above the exact cause of SUA is unknown, and depends on the way the arteries split and form during pregnancy.
The risk factors contributing to the formation of SUA are:
The attending doctors assess the risks for this condition through an ultrasound, especially the Doppler ultrasound. In most cases, the medical history of the mother and the family, and prenatal tests help the doctor deduce the possibility of or presence of an SUA. Here are the tests carried out to diagnose the condition:
These tests can detect the problem and determine if your baby will be affected. Mothers who are at risk of developing a two-vessel umbilical cord abnormality are asked to undergo a colour flow Doppler ultrasound scan around the 14th week of pregnancy. Ultrasound scans are normal in the 18th week of gestation to help detect a two-vessel cord.
While in some cases there are no complications, in others there are risks involved. The condition could affect foetal development and lead to birth abnormalities. Single umbilical artery complications do not necessarily harm your baby. However, certain risks that the baby is exposed to are:
The doctor will monitor the baby’s growth through ultrasound scans, even if there are no complications. When the low-speed ultrasound findings indicate the possibility of SUA, a high-speed ultrasound will be done. If the baby is diagnosed to have a single umbilical artery or other abnormalities, an amniocentesis, where the foetus is tested for congenital abnormalities using a sample of amniotic fluid, is done. High-Speed Doppler Ultrasound scans and colour flow scans could also be scheduled to view the baby’s development. If the baby is born with organ dysfunction, additional monitoring is performed in the NICU.
So far, there is no way to prevent single umbilical artery, but since there are certain risk factors that increase its possibilities and associated anomalies, a mother-to-be should:
Educating yourself and being able to make an informed decision is the best way to go for mothers. Remember that the phenomenon of two-vessel umbilical cord complications is rare. Even if present, it may not affect your baby. Always discuss your fears and concerns with your doctor and make an informed decision.
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