Okay, that makes sense. I was just curious because the more time you have up front, the easier it's going to be to get the time off without unnecessary friction. Hypothetically, if I were a manager and one of my reports told me "hey, I'm having a baby next Tuesday - can I have two weeks off?" I'd be pretty teed off. I left my last job partly due to a lack of understanding over what my wife's pregnancy meant for my ability to work the same hours as the rest of the team (I was the only one with a kid and nobody understood why it's important for me to go to OB/GYN appointments). Don't put yourself in that situation.

Tell your boss early and remind him/her often that there is a baby on the way and you're going to need this time off. The only way you can screw this up is by springing a huge surprise on your boss like the hypothetical above.

Good luck and congratulations on the baby!