My save game didn't stay saved repeatedly.

I am so sad and angry about this.

My two sims have one baby,and the baby is in family stuff's inventary everytime,when i need save game in building mode. (Still writed me a text : "System mistake" ...)

Because the baby is in the inventary and in the life mode too,it's impossible game save and text me this :

you cannot leave the plot because you have a child in your inventory. And when i save game - in build mode, when i loading game (this family game) again,it is doesn't SAVE ! ☹️ 

Please,help me with this.
Thank you.

Edit By Crinrict: Fixed formatting for easier reading