What Are The Symptoms Of Amniotic Band Syndrome?

Hi, i have a question about amniotic band syndrome. I delived a baby that was stillborn weighing 11 lbs 14 oz six weeks ago. I am a diabetic. I went for bi weekly nst's however I had no idea It had been 2 months before delivery when I had my last ultrasound. 2 and a half days before my scheduled delivery I had a biophysical profile where my baby passed 8/8. I went in for delivery at 39 weeks and there was no heartbeat. The doctor tells me that he thinks there was an amniotic band constricting the cord.Is this likely? does it happen in a matter of 2 and a half days?