Question: What is a three vessel cord?
Answer: A normal umbilical cord has two arteries and one vein. If you are having a mid-pregnancy ultrasound, also known as a fetal anatomy survey, your ultrasonagrapher will try to see both the arteries and vein during your exam. This is easier done with color Doppler ultrasounds, but can be done with your average ultrasound machine.
About 1% of all babies will have a two vessel umbilical cord, which is a single artery (Single Umbilical Artery) rather than two. When this is found, you should be referred for a more detailed ultrasound. The reason that another ultrasound is done is to double check the findings and to ensure that your baby does not have any abnormalities. About 20% of babies who only have one artery in the umbilical cord will have malformations.
Source:
Obstetrics: Normal and Problem Pregnancies. Gabbe, S, Niebyl, J, Simpson, JL. Fifth Edition.
