Understanding Umbilical Cord Blood Vessel Variations: A Concerned Parent's Inquiry

Question
I am 27 with a 3 year old with a chromosome deletion 7q35.  June 8 was the first day of last cycle.  At my appointment today they said at my last ultrasound they only saw 2 blood vessels instead of 3.  What does this mean, is there a name for it?  In my first ultrasound it was reported they saw 3 vessels.  I didn't see a Dr. today but a PA.  She said she doesn't know much about it.  So I don't know anything.  Please help if you can.  Thank you.

Jamie

Answer

A two-vessel cord (absence of the umbilical artery) occurs about once ini 500 deliveries. The cause may be aplasia or atrophy of the missing vessel. About 30% of these infants wilol have structural defects. There is also a strong association between fetal structural anomalies and placental vascular occlusion or thrombosis. Perinatal examination for such vascular defects should be routine.  However, if they did see 3 vessels in the first ultrasound, it is possible that they merely missed one of the vessels in the second sonogram. I would repeat the sonogram and see. In 25 years of practice, I have had many deliveries where there were only two vessels in the cord and I have not seen any detrimental effects or sequelae. Don't worry.