The Umbilical Cord usually has three vessels, two arteries that carry waste from the baby back through the placenta to the mother and one vein that carries nutrients and oxygen to the baby from the mother via the placenta.
I teach my students to remember it with the smilie face, Two a's and a V. a a
About 1.5% of pregnancies result in a single artery cord. This is a cord with one artery and one vein. In most cases it won't affect the baby, though in a few there is a chance of some complications.
This was the best thing I ever did! I went from getting the start of PND, then started taking my tablets and it levelled everything out and I could enjoy the time with my son.. I will be getting them again with my next child. L