Expect that your first week back after baby will be a big transition for you.
It's wise to visit work a week or two prior to your first day back. Be sure to bring your baby to show colleagues and arrange to meet with your boss to discuss your return to work.
It's best to arrange a short week when you first return. This will help to ease your transition -- there's going to be a lot to get used to. Better to have three days of heavy adjustment and two days off before diving in to the "real thing."