Amniotic sac found

[Laurenb03]

We went for our 12 week scan last week, our baby is healthy and they're sac is perfectly formed but they found an amniotic band above.
I have since had a midwife call to say they are concerned and would like me to go for a 16 week scan to keep an eye on it.
Has anyone experienced this and know how or why it's there?
Thanks in advance

I had this in my first pregnancy. Googled it and worried myself sick! Mine resolved itself and baby was absolutely fine. It is good they are following it up, I never got that or any information.