X.O.
I'd write her an email something to this effect..
"Dear Jane,
Thank you for being there for me during my difficult time. Bob and I have come a long way and are healing, but we find it is more difficult to heal when we have constant reminders of our loss. We would be very appreciative if you would not make mention of the miscarriages any longer.
Thank you for your love and understanding.
Love,
Betty"