I am not going to reiterate the advice given in the answers by @iKlsR and @Ashley. I want to add some more information; this is less of a solution, but more a cautionary tale.
This is a tricky question, as there is no real way of predicting the outcome of how a pet will receive the first newborn (or even subsequent newborns) into the family.
When my first child was a baby, we bought a Rottweiler, he was a beautiful dog, and well trained in obedience.
Our second child was not born for another 6 years (approx) and the dog never accepted the new baby. Our newborn would make little noises and the dog would growl. We had to keep the dog and the baby separated at all times. I could not risk allowing the dog to be near the baby, as the dog made it clear he did not like him.
We loved the dog (and the baby) so kept both separated.
We then had our third baby about 18 months after the second! Well, needless to say the dog never met this baby.
There were then two events which were defining and heart breaking.
The dog growled at me, when I went near his food bowl while he was eating. I was the dog's master, I was the pack leader, and had obedience trained him, walked him, bathed him, fed him and loved him! I had specifically trained him to allow me to take food from his mouth! Any food, bone etc and to be able to handle him in any humane manner; as I had seen cases of dogs not allowing owners to touch certain parts of their bodies.
He was feeling left out, and as an aging 55 kg Rottweiler he was becoming arthritic and not his happy easy going younger self.
One day I was with my little son, a toddler now and we had a iron gate. The dog was on one side of the gate and I with my son on the other. My little boy loved the dog and tried to reach through the bars to pat him. The dog snapped at him.
It was an agonizing time and with consultation with the local Veterinarian that I had to make the decision to euthanize my dog.
This was the same dog that loved and protected our first baby throughout his life.
Now this is a Rottweiler, he weighed the same as I did at that time and the amount of damage he could inflict would be far greater than a pug. Also, they are known to be more aggressive, having said that, I never totally trust any breed of dog outright with children, based on the notion of it being that particular breed.
Dogs don't have hands, cannot speak English and communicate (in part) with their mouths; through sound and with their teeth. This is something that should always be remembered when introducing dogs to babies.
Dogs are pack animals, and this is one of the leading issues with behaviour problems with dogs (their perception that they are higher ranking members of the packs than their humans). Your dog will have a firm notion of where he fits into his human pack. Some dogs do not accept an infant as part of the pack or a protected pack member (as offspring). Some dogs also become jealous of the attention bestowed on the infant. These two things may sound like they are the same thing, but they are actually subtly different.
Bearing these factors in mind I would follow the advice of the other answers and make sure you give your dog plenty of pats and show him how happy you are whenever you walk n the door.