It is important to keep your pets away from your infant child. Very often your pet will lick your infant's face or hands. At such a young age, your child's immune system is still very weak and it is easy for an infection to be caused by germs from your pet's mouth or paws. Remember that your pet is in contact with all sorts of dirt, including faeces. When your child is older, pet contact won't a problem.
You may find that your pet is jealous of your new child, since your child will be the focus of attention. Facilitate a good relationship between your pet and child by allowing your pet to be around your child while you are present. Give both your pet and child attention when they are together with you. If you are able to schedule it, make some alone time with your pet as well.
If your pet acts aggressive in your child's presence, be very quick to reprimand such behaviour. Your pet should soon work out what kind of behaviour is safe and acceptable around your child.
If your pet continues to be aggressive around your child, consult a professional pet trainer or vet.