Single Artery Umbilical cord

Hey everyone, so it’s not me, it’s my sister in law that was pregnant and found out today that she has the single artery umbilical cord. Umbilical cords are supposed to have 2 artery’s and 1 vein. It’s doesn’t have MUCH risk but it does have some and I want alleviate some stress and concerns so I was looking for anyone to give me some insight, if their baby had this problem and what the outcome was? Anything really to help her calm down.

She’s waiting for an appointment to get a better ultra sound but who knows how long that could take!