Starnur, I discovered I made a mistake here. I thought that the chart you put up was the progressed one, not the natal and transits, so instead of progressed Moon (which I thought it was) it was the transiting Moon conjuncting natal Mars which by itself, as Shining Star wrote, does not necessarily trigger miscarriages.
But I changed the words Progressed for transiting anywaysin my former post.
What can be said about the Progressed Moon is, that she is also square progressed Mars, like progressed Sun and those are two very important progressions to Mars.
Sometimes confrontational scenes with partners.
like Shiny wrote.
I dont think it is possible to see the cause of the miscarriage in a chart, apart from maybe stressful situations or an accident.
Looking at that Progressed Sun square progressed Mars that could indicate she maybe got into a situation where she was hurt. Progressed Mars is in her 4th (at home), transiting Mars in the 7th (by partner or other person?)
I dont particularly like the natal Saturn in her 7th in grand square with Mars, Moon and Mercury!(ruler 7th) and opposing her Ascendant and Venus. Pluto, ruler of her 12th house of secret things and selfundoing, squaring her progressed Ascendant also looks like some act of violence. I hope I am wrong, but you never know. It raises my suspicion a bit. She wont ever tell anyone if that were true and pretend all is fine etc. (Neptune exactly conjunct her Ascendant, Sun in 12). I hope I am totally wrong here and all was due to stress (maybe in connection with her husband) as you "were pretty sure that she was under stress". I have seen cases of abuse with these sort of charts unfortunately.