The Rhythm Method and the Standard Days Method are fertility awareness-based methods of contraception, and Natural Cycles is a digital birth control method. These methods have in common that they rely on identifying the user's fertile window, but they work in different ways and the effectiveness is different for each method.
Both the Rhythm Method and the Standard Days Method rely solely on period data to determine the fertile window, while Natural Cycles uses temperature data to detect the user’s ovulation in each cycle.
In a study looking into how Natural Cycles compares to the Rhythm Method and the Standard Days method, we found that Natural Cycles is able to more accurately identify the fertile days in each cycle than the other methods, meaning that it was able to give more green days – on average 61% after 12 cycles when using both temperature and LH data compared to 43% with the Rhythm Method and 58% with the Standard Days method.
Natural Cycles is also less likely to give a wrong green (non-fertile) day on the most fertile days of the cycle, the days before ovulation and ovulation day itself. When both temperature and LH tests were logged, the likelihood of Natural Cycles giving a wrong green day on these days was 0% (with temperature alone, the numbers were 0.31% on the day before ovulation and 0.66% on ovulation day). In contrast, the Rhythm method had a 0.80% likelihood of giving a wrong green day on the day before ovulation and 2.46% on ovulation day, and for the Standard Days method, these numbers were 6.90% and 13.01% respectively.
If you’d like to know more about this study, we have a summary of the results in our Research Library.