This method is recommended only for women who have very regular, predictable cycles and who have no reason to be concerned about STDs. Natural family planning requires a high level of education about the method and daily persistence in noting body changes as well as abstaining during fertile times. If you are interested in this method, please ask for more information from the clinic staff. Common wisdom is that it is better than nothing, but it puts the woman at risk for both pregnancy and disease, and it puts all of the power and method effectiveness on the man. No matter how good his control is, pre-ejaculate may leak, carrying disease or sperm.
Contraceptive methods do work.
Because research can't determine how many women who used a method would have gotten pregnant in a year if they didn't use the method, the only thing that can be measured is failure rates. Keep in mind that failure rates in studies apply to groups, not to individuals. Even the best method in the world won't protect you if you don't use it or if you use it incorrectly. If you are careful about using your method correctly, your failure rate may be much lower than others in the group. Using two methods at once dramatically lowers the risk of accidental pregnancy.