For everyone wondering about this method, it's called the sympto-thermal method and is not the same as the rhythm method. Planned Parenthood lists it as 99.6% effective with perfect use. See the "What is the Sympto-thermal Method" section in the link below:
99.6% is the method-effectiveness (i.e. the efficacy if used properly) or 0.4 unintended pregnancies per 100 "women years" (13 cycles)
Other interesting results from the study:
- the method-effectiveness rate found for this method is comparable to oral contraceptive
- 9.2% stopped using the method due to dissatisfaction
- Couples that had intercourse during the fertile period had an increased pregnancy rate of 7.5%
- This study was done in European countries and the pregnancy rate was lower than similar studies performed in developing countries
It's pretty spot on. My wife did this so we could avoid pregnancy for first few years of our marriage, and once we decided to try for one, only took one month for her to get pregnant.
99.6% is the method-effectiveness (i.e. the efficacy if used properly) or 0.4 unintended pregnancies per 100 "women years" (13 cycles)
Other interesting results from the study: - the method-effectiveness rate found for this method is comparable to oral contraceptive - 9.2% stopped using the method due to dissatisfaction - Couples that had intercourse during the fertile period had an increased pregnancy rate of 7.5% - This study was done in European countries and the pregnancy rate was lower than similar studies performed in developing countries