We have a couple a very spoiled yorkies and TBH the first person whonew about my pregnancy was the dog trainer as we were worried about how they would react to the baby (one of them was a rehome and was terrified of children...therefore she could bite). The trainer told us to start doing things as if the baby was already there:
-Not allowing them to the bedrooms and if you really want to keep the pecking order clear never ever allow them on your bed, if even after this the dog is still trying to be the leader don't allow him upstairs at all.
-I didn't allow them to jump onto mylap anymore (though I do now that is safe).
-The trainer also asked us to ignore them a bit, as the baby would take a lot of attention and if the dogs were already used to that they won't feel so bad.
But in general the key is toensure the dog nows that he's at the bottom of the pecking order, curiously, when they know that they become adorable and they seem far more relaxed, don't bark to visits, etc.
We didn't allow them to get very near to DS until DS started to walk, The dogs are lovely and very patient to DS, however, a toddler can do a lot of damage to a small dog and I supose that if the dog is in pain he is very likely to bite to defend itself, so we always keep a close eye on the 3 of them. So far is has been easier to train the dogs to respect DS than to train DS to be respectful of the dogs. But little by little is working, and the three of them seemto be having a good time.