Child's name for birth parents

What does your child call their birth mom and birth dad? My son is only a month old and won't be talking for a while, but I figure it isn't a bad thing to plan ahead. I have been calling her his "Mama Shanny". Her family's nickname for her is Shanny and when I asked her what she would like to be called, she said it was up to my husband and I. I don't like the idea of referring to her as Aunt as I have heard some people do because I feel like the minimizes the significance of her role in his life. Is Mama Shanny appropriate? I never want this to be something that causes hurt feelings and would love to get some advice on the subject.