You've got a couple of months left before the new baby arrives, and your faithful companion is still secure in the knowledge that she's Number One. It's time to get her used to sharing your affection. As with all important desensitization processes, and yes, that is what this is too, you'll need to start slowly.
If you don't want Pooch in the newly appointed "nursery", it's time to start prohibiting her access. Start by closing the door at night, or when you aren't home. If she ceases to see that room as her territory, she won't be as put out by being "put out". Gradually add during playtime to at night when the door is closed. Then after a while, usually a couple of weeks, start keeping her out when you are in there as well. Once it is firmly established that the nursery is a "no puppy" zone, you won't need to worry about Pooch hopping in there to play, and you won't have an incensed furball on your hands when you need to put the baby down, or change diapers.
Play recordings of a baby crying, and other various noises that little ones tend to make, like the ones found HERE. By playing these for a little while every day, not only will your dog get used to the sounds and start to take them for granted, but so will you. Crying at the volume a baby can wail at can be distressing for a dog who's never heard it before. I recommend starting them at a low volume, then gradually increasing it to a normal level.
When the time is drawing near and you have about four or five weeks left, start to sprinkle baby powder around the house to help her get used to this new smell. You might also want to start "borrowing" babies from friends, so the abrupt (to her) arrival of this little being that won't leave is not such a big change. Borrow baby blankets (unwashed) from the afore-mentioned friends as well, and let her get used to having them lying around. This is also a good way to get her used to not lying on a baby blanket draped along the sofa or chair as well. If she looks like she's about to get comfortable on a baby blanket on the floor, a firm "Off" and re-directing her to an appropriate place to lay down will set a pattern, and soon she'll be avoiding blankets that may hide a baby in the near future.
Part Three: Your New Baby is Here! Now What?
