I recently finished reading The Girlfriend's Guide to Pregnancy.
While this book isn't going to give you all of the hard, medical facts about all 40 weeks (and doesn't claim to), it definitely sheds some valuable light — and all the good, bad and ugly details — on the nine (10) month experience. Not to mention, it's pretty hilarious. I definitely recommend this book to any first-time mom-to-be.
Now I'm on to the next chapter:
It's never to early to start reading up on what to expect when the baby actually arrives.
And I'll note that I checked both of these books out of my local library. When I first found out I was pregnant, I was thrilled to start buying books, but take my advice — don't. If you really have the urge, go to a used bookstore because books on pregnancy and motherhood are usually only read once or twice, so used copies are often in like-new condition for a lot less than the cover price.
Also, I am very fortunate to have lovely friends and co-workers who have given me many books, hand-me-downs and otherwise, and I look forward to being able to pass these books on to others. Check in with friends who have had babies to see if you can share/borrow their references.
Lastly, search the Internet first. As long as you're reading reputable sites, like the What To Expect When You're Expecting site that pretty much provides you with all of the information from the book for free, you're all set. Most of these sites encourage you to make a profile, and you should. I receive two or three e-mails each week from the sites I subscribe to, including What to Expect, The Bump and Baby Centre, and I get all of the baby status updates and friendly reminders I could ever need to monitor the progress of my pregnancy between doctor's appointments.