What Is The Purpose Of Progesterone During Pregnancy Or After A Miscarriage?

Not to make this long, but my has personality disorder, most likely borderline and/or dissociative. She became pregnant late last spring and as you can imagine the hormone changes added to her rages and splitting. We needed to take time apart as the situation was deteriorating quickly. In June while I was visiting my son from my previous marriage, my wife called me demanding that I cancel my plans with my son and come immediately to her home in Canada. After I refused, she went haywire. She ended up changing her phone number and not calling me for a couple of weeks. When she finally did, she told me she had lost the baby and that she blamed me for stressing her as the cause. As irate as she was she was immediately talking about getting pregnant again and had mentioned that she was already on progesterone. It has been proposed to me that she may not have actually lost the baby and may be just staying away from me until she is in her 3rd trimester and would not be at much risk of losing the pregnancy. What is the timing and general use of progesterone in pregnancy during pregnancy or after a miscarriage?