I just want to firstly reiterate what Joeve has said about you being a good friend - supportive, concerned etc...

I don't really know if progesterone tablets would have helped your gf or not - I don't know the reason for her recurrent m/c, she would need to consider being tested for that and for the baby to be tested as well. Usually the reason for m/c is abnormalities but not always. I hope the Dr can give her some more information reassurance as to why. You certainly haven't jinxed her from your m/c. She is somewhat lucky that she has someone who has gone through the same thing having m/c & multiple ones can feel very isolating.

I have had two m/c prior to conceiving my DD (who is nearly 3 yo), so yes it is possible.

I wish your gf all the very best & hope she can find peace & closure