Help! MIL called me fat... twice.

Katie
So me and my Husband were at his family Christmas party on Sunday and we were standing there talking to his aunt & uncle and my MIL walked over and completely interrupted the conversation and pointed to me and said "Look, isn't she getting fat?." I stood there shocked and then his Aunt rolled her eyes and said "No, she looks pregnant and beautiful." And I just said "Thank you" to his Aunt and his Mom walked away. Let me say my MIL is very rude but more of in a really stupid socially awkward way rather than mean. But sometimes I can't help but wonder if she's trying to be mean because she says nasty things to me quite often. My question is this - should I ask my Husband to address it with her? It's the second time she called me fat and if there is a third time I may go nuts on her!