I had a low lying placenta with DD. I had a repeat u/s at 32 wks - still no movement. I had another u/s at 37 wks and it had only moved about a mm. So I did have a c/s. Mine was within 2 cm, can't remember the exact figure. However, my ob did say I was the first patient he'd had with it not over the cervix where it hadn't moved in his eight years of private practice. I had a very small baby and a little belly, so it may just have been me - not enough 'growth' for movement.

GL! I'm sure you won't have my problem. And you can ask for u/s right up until the end if you want more opportunity to confirm.