Uncoiled umbilical cord

I had my anatomy scan at almost 18 weeks and the doctor said that the umbilical cord wasn’t coiled like it should be and that most times they fix themselves. Well my other doctor called and said they are going to keep an eye on it and made sure I made an appointment for a scan in 4 weeks to check again. I read online that it’s rare, and some scary stuff but I can’t help but worry about it. The umbilical cord was straight as can be. Has anybody had this happen?