Can pregnancy be avoided using natural fertility methods? What is the success rate for avoiding pregnancy for someone who follows the method exactly as opposed to the "typical" user?

The Fertility Awareness Method (FAM) is highly effective when used correctly, but more than any other method, it is extremely unforgiving of improper use or cheating. The reason for this is really quite logical. If, for example, you misuse a diaphragm or condom or even forget to take the Pill, the chances are quite high that for any individual act of intercourse it probably wouldn't matter anyway since you wouldn't necessarily be in the short fertile phase of your cycle. The Fertility Awareness Method, of course, is the exact opposite. If you disregard the rules, by definition you are having unprotected intercourse precisely when you are potentially fertile.

To use the Fertility Awareness Method effectively, you need to understand this and most importantly, you need the necessary motivation to avoid pregnancy. As the major studies make clear, if you lack the latter, you will indeed be taking substantial and foolish risks.

The Fertility Awareness Method, if understood thoroughly and always used correctly, is extremely effective in preventing pregnancies. Indeed, it is so effective that the weakest link will be the barrier method you use, if you choose to have intercourse during your fertile phase. If used perfectly and you abstain during those days (as done with Natural Family Planning), the chance of becoming pregnant would be approximately two percent over the course of a typical year. According to the 1999 edition of Contraceptive Technology, this is a lower failure rate than any barrier method. If you correctly use a barrier throughout the fertile phase, then the chance of your becoming pregnant would be close to the method failure rate of the barrier you use.

But the typical user rate goes down substantially to about 10 to 12 percent, although you should understand that in all the studies for which the stats have been collected, the users make clear that many times they chose to ignore the rules for when they were most fertile. Given this incredibly important fact, then you can see how you can increase the method's effectiveness simply by following the rules!