Pregnancy doesn't really affect your ability to work (except for complications that require bedrest, and even then you work from home). A newborn does require care from the mother, but many women are able to return to work full time after 6 weeks (and some as early as 3 weeks). She'll probably be on leave for a few weeks after baby arrives, but I'm sure she'll be able to keep an eye on things even while she's gone (this is why the night nurse was invented).
A baby and a career are not mutually exclusive, I just wish people would stop assuming that they are.
Another point to consider is that you can rarely get away with building a native mobile app alone. Unless you create a beautiful utility that is a standalone experience, you'll want to be able to re-engage users via email and perhaps spread the word via Facebook or Twitter, and that requires that you have a regular website for people to land on, and perhaps interact with your app a little bit to increase the chances that they'll download it.
The look book was awesome, it brought all the invitations on the site to life. You could curl up on a couch and flip through beautiful stationery at your own leisure. It made it a pleasure rather than a chore by simple getting it off the computer. Tracy, where were you when I got married? I was impressed that Tracy had to learn pdf scripting to pull it off, she learns just about anything, and fast.
Mmmm alas, I didn't learn PDF scripting (eugh, one of the reasons why I dropped my original startup idea) — it was all painfully done by hand in InDesign. That said, we're looking at scripting for this time around!