There are a number of devices and hormonal tests that are marketed with FDA approval for identifying the fertile time of the cycle. To date, none of them have been FDA approved to help avoid pregnancy. Such approval expects a high standard of technological effectiveness to identifying fertility and infertility. Right now, learning the method through classes is the most effective way to practice NFP. Some women find the devices reinforce what they have learned in classes, providing them with more confidence while learning. Performance of Fertility Awareness-Based Method Apps