does it actually work?

Yes! Creighton University (the institution the method was named after) did extensive studies since the start of the method to test this method's method- and use-effectiveness. They studied thousands of couples across the country over tens of thousands of months. The method effectiveness for avoiding pregnancy was 99.5%! That's the same effectiveness as the Pill, without any​ side effects, hormones/chemicals, or devices. There is no method (natural, pill, IUD, condom, etc) that is 100% effective. 

can we change our minds? 

Your intention with the system (to avoid or achieve pregnancy) is completely up to you, your spouse, and God. Because of that, and because you are not taking any harmful chemicals/hormones or have any device implanted in you, you can decide each month whether you plan to grow your family. Talk about freedom! 

can we use it to achieve a pregnancy? 

Absolutely! Not only can you use your observations to identify the best days of fertility to conceive, but you also have the opportunity to assess your reproductive health before you want to conceive. We want to make sure you are healthy and ready to successfully conceive and carry a baby to term, and we will do all we can to help prevent unnecessary miscarriages.