If you have a baby, and a dog, you need to watch the dog every moment for any signs of stress.
I suggest keeping your dog in a kennel cage until you are sure that the dog has adjusted to the new family member.
I would start using the kennel cage gradually in the weeks before the birth.
I have never trusted any dog we’ve owned with babies and small children. We didn’t have a dog until our son was 8...so I didn’t deal with it within our family.
But since all our dogs have been rescues, when my grandnieces or grandnephew came over and they were babies, or toddlers, I restricted or watched the dog closely when around the kids.
Being rescues, you never know what their past is, and some dogs give no warning before a bite.
I’m sorry, but either have a baby, or have a dog. If you choose to not have a baby because you can’t bear the thought of giving up your dog, then you don’t need to have a baby anyway.
What the heck is any 2 day old baby getting that close to a dog anyway
If you have a baby and a pit bull, one or the other needs to go. You can make the decision or you can let the pit bull make the decision.