Monthly Cycles is a personalized and easy to use tool to track, monitor and manage your monthly menstrual cycles. The program calculates your fertile days and. The best period tracking app on iOS! Period Tracker is a classy, pleasant, and discrete interface to track your periods, daily moods, health. Tracking your menstrual cycle with an app isn't just a way to keep from being blindsided by an unexpected visit from Aunt Flo. A new wave of.