Can someone talk about my girlfriends abortion in court when the court is not about her?

So my girlfriends mother is in court with her grandchildren's mother for rights in seeing her grandchildren. It is a very complicated matter, and to me, it has been blown way out of proportion. The mother of the children recently said that if she goes to court over this, she would say something about my girlfriends abortion in court. She is saying this because only a very few people know about it and it is a secret that bothers my girlfriend tremendously. It happened a long time ago, and only my girlfriends mother, grandchildren's mother, and myself, know. Can she legally say anything in court about this? This memory for my girlfriend is a very dark one, and I know that she still feels lingering emotions from it, even though it was at least 10 years ago.