Any dog, no matter what breed, can get along with children, and on the flip side of that, many dogs do not. Breed does not matter one iota. Children have smells and make noises that can bother some dogs, whereas other dogs don’t care. To some dogs, the high pitched noises, like crying and cooing trigger prey responses in many dogs. But, it sounds like your dog has more fear towards the baby. Regardless, you do not want your dog to fear the child. Fear can also cause issues. Fearful dogs can become aggressive dogs, but that isn’t always the case, but it is something that you need to consider.
Pit bulls are people dogs. If your pit bull doesn’t take to a stranger right away, that causes me to have a bit of concern. But, not all pit bulls follow the typical “people dog” characteristic, as all dogs are individuals, just like people are. Each dog needs to adjust in his/her own way, and be taught how to handle things. My first suggestion would be to speak with a professional trainer about the situation at hand. They will be able to help much more than a forum online!
If your dog has already growled at the baby, that is a warning flag right there. You must make sure that the dog is monitored at all times when he is anywhere near the baby. The baby may make sounds thay your dog doesn’t like or even fears. He is 7 years old, and has been set in his own ways with the same people in the house. Now, for 9 months, things have changed. There is this strange, noisy, and odd smelling critter taking up residence. The best thing to have done was to start working with him prior to the birth to get him prepared for baby. But, if you didn’t, it still isn’t too late, but now you will have to be incredibly diligent in everything that you do, and again, it would be VERY wise to seek professional assistance.
First, never allow the dog in the baby’s room, ESPECIALLY if you are not present. That room should be off limits to the dog.
Make sure that your dog knows his basic obedience, such as sit, down, and a combination of those with stay. It is so important that your dog know these commands forward and backwards, as that will help you have control of the dog when in the presence of the baby. It is also important that your dog know to not jump up on you when you are holding the baby.
Your dog should constantly be familiarzed with the scents of the baby by allowing him to constantly smell clothes, dirty diapers, baby food, formula, burp rags, bibs, etc. Babies give off all kinds of odors that your dog will not be used to. Of course, give these smells to your dog without the baby around. Do not allow your dog to smell the baby directly!
Make sure that once baby starts moving around on his own, that the dog is not near the baby. Babies tend to make movements that are playful in nature and normal for young ones, but to a dog who may fear the child and maybe confused on what this creature is, those movements could spark a natural instinct in the dog. The dog becomes agitated, and could hurt the child. This is what you are trying to avoid. Sometimes keeping the dog on a leash or in his crate while the baby is out is a good thing to do. But, keep the baby away from the dog. If the dog feels “threatened” while on leash or crated, that could cause potential problems. Only you know how your dog reacts on leash or crated.
Make sure that the family continues to treat the dog as he was treated PRIOR to the baby’s arrival at home. Make special time for the dog when baby is not around. Include the dog in activities with the baby, within reason, of course. But, you need to get the dog as comfortable as you can and as soon as you can before you really include the dog with a lot of baby activities. Once the weather becomes nice, walking with the dog and baby (someone else walking the dog) is one way to begin a bonding process.
When baby is around, give your dog a yummy treat, chew toy, or even a new toy to keep the dog occupied.
With a lot of hard work and diligence on your part, things will work out. But, you really should seek the advice and help of a trainer to get your dog socialized to strangers before you even think about introducing dog to baby. To your dog, baby may be a stranger that just won’t go away!
Best of luck to you and the family!