Dogs need time to adjust to a new baby in the house, and that time shouldn't start the day you bring baby home. The time and energy that you're going to focus on taking care of your baby can create a stressful environment for a dog that hasn't been prepared, as all that attention you used to lavish on her is being channeled elsewhere. Helping your dog adapt ahead of time paves the way for a healthy relationship between all your babies, whether they have two legs or four.
Carry a baby doll in the weeks leading up to the due date. Keep the baby doll swaddled and with you when you're with the dog, and practice activities like walking the dog with the doll in a stroller. This helps her adjust to your new routines and priorities without you having to worry about your actual baby.
Put up any barriers that you plan on using when the baby comes home. Your nursery should always be off-limits to the dog, but that's just one example -- you may wish to section off other rooms throughout the house so the dog and the baby can both roam free at the same time. Using baby gates, section off these rooms now and give your dog time to get used to staying in one room at a time.
Arrange for play dates with other babies, even if you haven't had yours yet. Invite friends with babies to bring them over, so your dog can get used to a baby being in the house, along with all of the smells and sounds that come with it. Just like you will with your own baby, always carefully supervise any interactions your dog has with a baby.
Ensure that your dog continues getting the attention she needs once the baby comes home. Keep her on a consistent routine when it comes to feeding, playing and walking. Another useful strategy is to keep one parent on baby duty with another parent on dog duty, and rotating "shifts." This way, your dog never feels neglected, which could otherwise stress her out and make her resent the baby.
Reward your dog when she behaves around the baby. Keeping the dog away from the baby at all times is confusing to her and hinders her ability to adapt to the baby. When they are in the room together and your dog behaves, praise her and give her treats -- she'll learn to associate the baby with good things.