Fertility charting is certainly a reliable and empowering means of family planning.
Avoiding pregnancy using fertility charting requires a personal involvement. It is not just about using an App/device/site and following its recommendations. It is about becoming intimately familiar with your fertility patterns and understanding the benefits, responsibilities and risks of this contraceptive method.
The principles of chart interpretation for pregnancy avoidance and pregnancy achievement are significantly different and unfortunately not just the reverse of each other.
FertilityFriend.com data tracking can be used for pregnancy achievement, cycle health monitoring or as a data tracker for other purposes.
FertilityFriend.com interpretations/analysis though are totally tuned and geared to help you get pregnant and would put you at great risk if you used it to avoid pregnancy. Using any of FertilityFriend.com's chart interpretations in reverse will not work either and will put you at risk to get pregnant.
Avoiding pregnancy using fertility charting is a different approach altogether. If you plan to use fertility charting (or Fertility Awareness) to avoid pregnancy we recommend that you get in touch with a Natural Family Planning or Fertility Awareness counselor and get a specific training for that purpose.