2 vessel cord?

Brittney
Yesterday I went back after some questionable results from my 20 week detailed. We learned that the cord only
Has 2 vessels (one artery and one vein) and it's suppose to have 2 arteries and one vein.... I'm not being placed on high risk and will now go to my doc, in addition to every week for my shot to help with development due to my 4 early deliveries, every 2 weeks to be hooked up to a monitor to monitor his heart rate and to do a sono and be sure he is growing as he should..... I had never heard of this and wondering if anyone else experienced this.