RP: having placenta problems

I had a partial abruption with Peyton around 22 weeks, (this is when she had her stroke) and they attributed it to my low lying placenta, even though I had been cleared that it had moved a few weeks prior.  (I had a lot of bleeding on/off the whole early pregnancy).

So, this time i'v been seeing a regular OB & the peri.  I saw the peri once at 13 weeks and again today for an anatomy scan.  My regular OB did an anatomy scan at 18 weeks and everything was normal.  However, today, the peri came in and showed me 'areas of concern' on my placenta.  He showed me how the majority of where it attaches to the uterus was non functional.  He said the villi were not really functioning, or something to that effect.  He said about 1/3 to 1/2 of the placenta looked like this.  The majority along the top and then in various spots along the rest of the placenta. 

He said that this can lead to abruption, IUGR or in some cases, it's just benign and won't get any worse.  With my history of abruption, i'm pretty much freaking.

I called my friend who did my other ultrasound and she said she didn't remember seeing any thing like that 2 weeks ago but she is going to pull the scan and double check & do some research for me.  Which makes me freak more, because now i'm thinking what if it got this bad in 2 weeks.  What about 2 more weeks?

Of course I have every worst possible scenario running through my head and they all suck. 

Does anyone really know anything about this whole, 'not fully functional' placenta?  

The peri just said that I would need regular growth scans but that he needed to talk to my high-risk ob for a course of action.  He also said that a placenta that looks like this is sometimes associated with a specific clotting factor which I haven't been tested for.  (And i've been tested for a lot).  He also is wanting to switch to heparin so that the baby is protected from clots as well, he said that the lovenox doesn't offer protection to the baby.  But again, no course of action until he speaks to my OB since i'm technically under his care.