Anyway, a slightly amusing paper says that couples who use such "fertility awareness" methods do have the same amount of sex, it's just that they have it more often on "safe" days. This makes for a "selling point". The claim as to the effectiveness of the methods seems pretty big:
"In earlier field trials Institute researchers determined the efficacy of the Standard Days Method and of the TwoDay Method to be to be greater than 95 percent and 96 percent respectively when used correctly, making them more effective than the condom or diaphragm. The Standard Days Method is for women with cycles between 26 and 32 days long. To use the method effectively, women can use a visual tool called CycleBeads® to monitor their cycle days and identify the days when pregnancy is most likely (days 8 through 19)." (Emphasis mine.)
Cyclebeads? Cute name. You can see what they are here. Just a way of counting days.
I am pretty skeptical about this, just because it sounds too good to be true. However, the claim is as follows:
"According to the 1998 edition of Contraceptive Technology, 85% of women who use no method of family planning will get pregnant in one year. The percent of women who will become pregnant during the first year of perfect use of a "user-controlled" method is as follows:
- Cervical cap, 9 - 26%
- Spermicides, 6%
- Diaphragm, 6%
- Female condom, 5%
- Male condom, 3%
- Birth control pills, 0.1 - 0.5%
- Standard Days Method, 5% (2002 Georgetown study)"
Is it fair of me to ask what the "non perfect use" rate of success of each method is? Or does that just make meaningful comparisons too difficult?