General Discussion

Many years ago, as a preschool teacher, it wasn't uncommon for the 2 and 3 year old girls at the daycare to be fascinated with women who were pregnant, especially if the woman was their own mother, aunt or family friend. They would do the same thing your grandaughter is doing. One little girl would pretend to breastfeed her baby, just like mama.
By the time they were four, most of them seemed to lose interest. Your granddaughter may become less obsessed as she gets older.
Haven't seen the Barbie is pregnant videos.
All we can do as caring adults is to gently support our grandchildren, and let them know there are other things they can do in addition to, or besides, being a mom.