someone showed me this really interesting PDF about 'the fertility awareness method of birth control. i gave it a google, and this is what came back:

Fertility Awareness Method (FAM) is a collection of practices that help a woman know which days of the month she is most likely to get pregnant. A woman can learn when ovulation is coming by observing her own body and and charting physical changes. She can then use this information to avoid or encourage pregnancy. The most effective way to discover YOUR fertile time is to practice all of the techniques described here.

Fertility Awareness increases a woman’s understanding of her body and her menstrual cycle.

from FABC

Here is ths Downloadable PDF, a really neat document.