I used several pregnancy-tracking apps when I was pregnant with my son. I always found them slightly informative, but mostly gimmicky. Recently, though, I found one I actually do like called Sprout for iPad and iPhone.
My sister is having a slightly more complicated pregnancy than mine was, so I went searching for an app that I thought would bring her comfort without scaring her. (If you want to know what I mean by "scary," watch the birthing video in an app called BabyPump Pregnancy Pro. Or actually, maybe don't.)
Sprout is an app that is not meant to scare you. It intends to inform you about the little person growing inside of you. Sprout gives you images and information about how your baby is forming at any given week or day of your pregnancy. It tracks the days, weeks, and months, and gives you a countdown of how many days until your due date.
The images of the baby in utero are a little creepy, but so are sonogram photos. As Tina Fey once said about her own sonogram images, "There's a reason this is not see-through." Each week, a new image will have touch points where you can learn more about how any given body part is forming. For example, in Week 8, touching the arms will bring up this little nugget of info: "Arm and leg buds are now emerging. At this stage of development they look more like small paddles than limbs."
The tab labeled "The Doc Says" gives some generic medical advice about how you should be feeling, eating, and exercising. A disclaimer is careful to note that the app is not meant to replace your own physician's advice but there are some useful factoids here. It even takes into account emotional changes, which is much appreciated, because pregnancy and emotions go together like pita chips and Nutella or at least they did for me, in my first pregnancy. (Don't knock it until you try it.)
The app also has a doctor's appointment planner, but I never relied on it; I preferred to use Google Calendar so that I could share appointments (and reminders) with my husband. I did like the note tracker, though. You can keep track of questions that you want to ask your doctor when you get there, so you don't forget. I did use my iPhone for this with my doctor, and he humored me even when my questions were silly. (Such as: "If I poke it through my stomach, will it move?")
Some other tools include a weight tracker (which you will probably grow to hate), a kick counter for when your little one starts doing drum solos on your uterus, and a contraction counter for when it is go-time.
A few other useful tools include a to-do list and newborn essentials list that gives you an idea of the kind of baby gear you will most likely need. There is also a hospital-bag suggestion list, which I find useful, because it reminds you of things you might not think about. For instance, there's a reminder to bring change for the vending machine to buy food for a restless daddy. Good idea!
The app also allows you to post this information to Facebook to share with your friends, although I'm pretty sure most of your friends won't really want this kind of detail. I would probably unsubscribe to updates like this if a friend started posting them. A simple "I'm pregnant" status update is usually all the information I need about someone else's pregnancy. Nevertheless, it's an option.
The developers of this app just released a sister app called Pregnancy Journal, which allows you to journal your pregnancy with notes, pictures, and more. When your baby is born, you can order a physical copy of your journal that looks like a professionally made photo memory book. It is a very neat option. Books start at $9.99 and up.
Sprout is optimized for both the Apple iPad and iPhone. The app costs $3.99 in the iTunes store.