When I was pregnant I used both the hello belly pregnancy tracker and app and also the BabyCenter Pregnancy Tracker & Baby App.
Although both pregnancy apps were great I preferred to use the BabyCenter Pregnancy Tracker & Baby App to track my pregnancy and would recommend the BabyCenter App.
Still the other one was great and did you know too that now you can use an app that tells you when you're pregnant?
Yes you can although you still need to pee on a stick your smartphone can detect pregnancy.