For many people out there, their dog is their first "baby." For some, this may be their only "baby" if the owner is not having children in their dog's lifetime or has children that have grown up. My own dogs were my first "children" and I can tell you that it is very very difficult to add a human baby to the mix without some upset on the previous family dynamics. Thankfully, I did quite a bit of work to get our family ready for our first baby and while I did encounter some serious problems with my dogs and children, those problems did not occur till my baby was no longer a baby (past her first birthday).
Bringing home a new baby is going to affect the parents, the pets and the baby. Therefore, you have three different parties to prepare for this new life. While no one can foresee exactly how daily life will play out with a new baby, there are things that are going to be set in stone that can be practiced and prepared for.
Dogs
I got all my baby equipment as soon as possible so my dogs could get used to it. They needed to not be fearful of the stroller, swing, crib, bouncy seat etc. I also wanted them to know those things were not toys. A little dog will need to learn that the bouncy seat or plush floor tummy mat is not hers to lay on! I even went as far as getting a baby doll and placing it in the equipment, teaching my dogs to heel next to the stroller with the baby in it and cooed and fawned over this plastic doll in the rocking chair, on the couch and carried it around. To desensitize them to crying, I played youtube videos of infants crying and gave them treats (open bar) while the crying occurred so they would not be stressed over crying. For fun, I even taught them to fetch a diaper on command! When my daughter was born, we had a good friend take our dogs for a few days while we were in the hospital and while we got settled at home for a day. I didn't want to be worried about the dogs on my first day home with my new baby. When the dogs did come home, I made sure to greet them away from the baby and give them lots of attention. Then we let them sniff our daughter in her carseat while she slept. I still remember feeling incredibly tense as my female dog Lucy pretended the baby didn't exist, and my male dog Lex, was tight as a bow string and I thought he might perceive her as prey. Turns out he was just ecstatic over her and became quickly obsessed about her whereabouts and wanted to not be out of her sight.
People
As hard as it is to imagine, try to imagine what your daily life will be like after baby. Will your spouse take over dog walking and feeding? Will you only give the dog fetch time in the evening after dinner? Will the dog no longer be allowed in the bedrooms and be sequestered to one end of your home? Give yourself a month or more before the birth of your child to start enacting the new routine so the arrival of the baby will not be to blame (in the dog's mind). It is better to ease into the transition of a new routine before you are flustered with a newborn as well! Newborns are a lot of work, yet not in a weird way. They require quite a few feedings in a 24 hour period, but they sleep a lot. I found myself with free time (but a baby on my chest) in which I would toss toys down the hall for the dogs. I pre-stocked my freezer with stuffed Kongs, bought a few new maze toys and bones that I could offer them during lazy days. Once I felt better, I learned how to use my baby carrier (like Ergo or Becco) and realized how transportable my baby was, thus enabling me to walk the dogs or get chores done.
Baby
How on earth can you prepare a fetus for dogs you ask? Well, I like to think that because of my daughter's exposure to flyball tournaments and practices as well as dog training sessions, that she got used to barking in the womb! To this day she will not wake if dog's are barking, yet my son (who was not exposed to random barking in the womb), wakes up at any barking. Once the baby is born, you can start his/her life with your dogs by simply not forcing a relationship with them. It is very tempting and unfortunately encouraged, to get the baby around the dogs. I can't tell you how many pictures I have of my sleeping daughter with a dog on a blanket with her, her feeding dogs snacks, her playing with their toys, crawling in their crates, petting them. I wanted her to be gentle with dogs, love dogs from an early start and while I did succeed in teaching her to be gentle, I also taught her to be drawn to dogs and teaching a toddler to play with dogs is NOT a good thing. As she got older, the dogs became uncomfortable with her advances (that is another story, and is on the blog under Lex etc.). However, knowing all this with my second child, I never pushed any interactions with dogs. I don't have a single picture of him sitting with a dog, touching a dog, feeding a dog and I can tell you that my dog Lucy, is very very happy that she can be in the same room with us without my son bothering her one bit.
For more information on dogs and kids and "demagnetizing" children toward dogs, see this website;
http://www.dogsandbabieslearning.com/2011/01/24/mamas-dont-let-your-babies-get-magnetized-to-dogs/