Scan today with rare diagnosis

Angela
So, today I had a scan that I thought was pretty low risk, mostly since getting over a sub chorionic hematoma everything has been A-OK 
But today I found out that my LO has umbilical cord varix. It's so rare that not much is known about it. And hardly any studies have been done. 
Absolute worst case it can come with other anomalies or it ends in miscarriage or stillbirth. 
But sometimes it resolves itself. Sometimes it doesn't and then you have to be induced early on because it can cause Fetal distress. 
I'll now have a scan every week until it resolves or she comes out early at 37 weeks. I'm at 31+3 so not too worried about preterm.  
No known cause or solution.  They will just watch it for the next 5 weeks. 
The word stillbirth has me a bit freaked out. Having said that she's super active. But now I worry about all the quiet times.  
So, I guess I just wanted to know if anyone had heard of it or has it now or had it in a prior pregnancy
Thanks for listening. :) (bit worried)