placenta accreta

Has anybody here been through this with any pregnancy?  At my NT scan, the tech alerted us to the strong possibility that I might have it.  The doctor wasn't ready to dx it, but wasn't willing to say no, either.  I'll go back at 18 weeks for another Level II scan to see if it was just a fluke or if it has gotten any worse/definite dx at that time.  I have had two D&C's from miscarriages and a c/s for the twins.  The placenta was supposedly up higher and away from my c/s scar, but previous D&C's could have caused lining damage anywhere...