Comparing Effectiveness Rates
While NFP’s effectiveness can be compared to that of contraception, there is an intrinsic difference between the two. Natural Family Planning effectiveness pertains to a couple’s ability to determine fertile and infertile times of a woman’s cycle. The effectiveness of contraceptives relate to their ability to prevent a pregnancy from occurring or from continuing. The user effectiveness of NFP also involves the ability of a couple to refrain from sexual intercourse on days that the method indicates are fertile if they intend to postpone a pregnancy. The user effectiveness of contraception relates to a woman/couple using devices or taking pills as specified if they intend to postpone a pregnancy.
This graph compares the method effectiveness of various forms of contraception with NFP. The Sympto-Thermal Method (STM) of NFP taught by CCL in this course is extremely effective in determining the fertile and infertile times within a woman’s cycle. The 2007 German study (hyperlink) also showed that couples who have a desire to postpone a pregnancy during a given cycle, can do so using NFP with the same accuracy as contraception.

R. Hatcher, et al., Contraceptive Technology, 18th revised edition., New York, NY: Ardent Media, 2004, pp. see Table 31-1