Pregnancy tracking apps certainly are not a substitute for professional medical advice, but they can be fun and helpful when it comes to tracking a baby’s growth over time. In his report this week, PC Mike Wendland offers three great choices for expectant mothers. Hear My Baby Heartbeat App is so popular that it’s currently atop the App Store’s medical category. You use just your iPhone microphone to record and share your baby’s sounds. The app isolates the baby’s sounds and amplifies them making them easier to detect and hear. The app is $4.99 for iOS. HiMommy Has you enter your due date to receive daily information about your little…