My suggestion is very simple and I would love it if it was implemented, if it is possible, obviously:
After a certain period of pregnancy (e.g. from 50%) the belly would start to moving and get more and gets more agitated baby kicks until the delivery time.
And during the delivery, the belly would get smaller as the babies are born (this doesn't happen in the last update 42, it just stays big until the scene changes).
If it doesn't possible to make this, there's no problem, I like the game to kill time.