How effective is Natural Cycles as a contraceptive?
Perfect use failure rate of 1.0, which means that 10 out of 1000 women who use the app for one year and who become pregnant will do so either because:
a. They had unprotected intercourse on a green day that was falsely attributed as non-fertile (i.e., method failure); or
b. They had protected intercourse on a red day, but the chosen method of contraception failed.
Typical use failure rate of 6.8, which means that in total 68 women out of 1000 get pregnant during one year of use due to all possible reasons (e.g. wrong attributed green days, having unprotected intercourse on red days and failure of the contraceptive method used on red days).
Having studied over 22’785 women, who were 29 years of age on average, and analysed 224'563 menstrual cycles this is the largest prospective study carried out not only on Natural Cycles, but on natural contraception as of yet. It demonstrates the efficacy of Natural Cycles as a method of contraception by analysing women’s real-life data.
Be sure to refer to the instructions for use to ensure you are using Natural Cycles correctly.