Hi, its definately possible to do but not until your baby is fully potty trained. Both my yorkie girls and my pekingese sleep in bed with us. My pekingese potties outside so he never gets up through the night. My one girl is quite small and even with puppy steps she can't get on and off the bed. However, she potties before we got to sleep and she's fine all night until morning. My other girl uses the steps and will get up through the night to go potty (if she has to) and will come right back to bed. Again, definately possible but only once they're trained, unless you want pee pee in your bed, LOL
Good Luck with the training.