I think the most important thing is to remain consistent with your dog. The stories of dogs reacting badly and inflicting harm on a new baby invariably are traced back to the dog believing that in some way the arrival of the baby has meant a punishment for them (ie when DD1 was born there was a story in the news about a dog that mauled the new baby after it had been on a 'holiday' with the grandparents while the new parents adjusted...for this dog, it was a punishment that it was sent away and relegated to a new pecking order without warning).

Clear boundaries are best instituted while you are pregnant regarding access to baby's room/your bed/couch etc.

Also a good idea to start thinking of the different ways that you will interact with the dog once bubs is here (eg. if they are going to be walked with the pram then have the pram set up early and in the living area so they get used to seeing it and seeing being occasionally moved...good for nervous dogs as well)

sniffing of the clothes of both you and baby is also a brilliant way to have the dog recognise the new smell and not be too shocked when the baby arrives and when you arrive...you will smell different as well especially with the milk coming in...my dog loved it...she became all puppy-like around me ).

In all honesty though most dogs do really well and adjust with very little worry. sometimes the crying can freak them out but after a few days it becomes part of the background noise