has any1 used an ovulation monitor to not get pregnant?

While ovulation monitors can be helpful when used in combination with fertility awareness, they haven't reached the degree of accuracy necessary to be effective in avoiding pregnancy by themselves. There is a study that showed the sympto-thermal method slightly over-estimates the number of fertile days and the Clear Plan Fertility Monitor slightly under-estimates the number of fertile days. If you're interested, I can probably find the study again. Personally, I'm DYING for a company to come out with a monitor that can be used. The technology is there but I guess at this point it is too expensive.