Catlover, sorry you have been through this, I have had similar losses at up to 13wks, apparently normal (scanned, seen moving etc), but something went wrong.
I'll tell you my experience, and make a suggestion!
I saw a consultant, top person in our area for "old" mothers (I was over 40).
He said as we get older, we are more likely to have autoimmune factors, some of which he could test for, and some of which he couldn't, so he recommended the following to all women with similar loses, especially if older, and claimed "good success" with his "older mothers" (I guess that probably means anyone over 35?).
I was to start 5mg folic acid per day (a very large dose), while TTC and until mid pregnancy.
Mini- aspirin every day from the day of positive preg test to 30wks preg. I think they are 85mg tablets (equivalent to about a 5th of a normal aspirin I think).
My next preg after starting the above, was successful, at age 42. Those medications are both anti-inflammatory so they are dampening down immune responses within the body.
After DS was born I continued to suffer health issues which in retrospect, were almost certainly autoimmune in nature. After going Gluten free all of these issues have resolved.
My suggestion is this (because you mentioned pcos and a couple of other things), something that can do you absolutely no harm, and might help you, is to adopt a gluten free/wheat free diet... Many people with pcos and other inflammatory autoimmune related conditions have found gluten free/wheat free a big help.
If you are interested, in trying it, google "whole30", and/or read Marksdailyapple blog (it has a searchable archive with lots of info on exclusion diets, fertility).
I know it's not going to help everyone, but maybe worth giving it a go?