The Effectiveness Of Natural Family Planning

by John Kippley

Part 1 — INTRODUCTION TO EFFECTIVENESS

Part 1: Introduction: The Effectiveness of NFP
Part 2: Method Effectiveness
Part 3: User Effectiveness
Part 4: The Ethics of FDA and ACOG Regarding NFP
Part 5: References

There is no doubt about it: some physicians are well informed about Natural Family Planning and they strongly encourage its use. Some are so convinced about the medical and moral hazards of unnatural forms of birth control that Natural Family Planning (NFP) is the only form of conception control they will offer to their patients.

However, the fact that some methods of NFP can be 99% effective in the avoidance of pregnancy seems unknown to most of the general public--including many health care professionals. The fact that the fertility awareness which is a key element of modern NFP is also very helpful to couples of marginal fertility in seeking pregnancy is also unknown. Ignorance breeds prejudice, and this is just as true regarding NFP as it is about other areas of life; it applies across the board from the "man in the street" to the editors of health journals and women's magazines.

There are three basic reasons for widespread ignorance and prejudice regarding natural family planning.

First of all, many health care professionals are uninformed about the modern methods of natural family planning. Therefore, they group various natural methods that are entirely different together under the title of "rhythm". On the contrary, it is absolutely necessary to distinguish between different systems of natural family planning, just as it is necessary to distinguish between different unnatural methods such as the Pill and a postcoital douche. For example, what health care provider would average the best case for the Pill and the worst case for the douche and state the result as the effectiveness of artificial or unnatural methods of birth control? It is no less absurd to apply that procedure to various natural systems of family planning.

Secondly, many people including health care providers, are skeptical of anything natural. Their orientation is so much towards drugs, surgery and devices that they find it difficult to believe that common ordinary married couples can understand their mutual fertility well enough to achieve the same effectiveness associated with powerful drugs.

Thirdly, some organizations that specialize in or are oriented towards unnatural forms of birth control have been unfair in their treatment of NFP. Old rhythm studies from Latin America with low effectiveness rates are quoted and requoted, but a recent and well designed study by the U.S. Federal Government showing a 100% method effectiveness is ignored or misquoted.

One purpose of this pamphlet is to review the very solid basis for the statement that the Sympto-Thermal Method of Natural Family Planning can be used at the 99% level of effectiveness in avoiding pregnancy, using the same statistical criteria used for unnatural methods. This review makes that claim only for methods which include the temperature sign, and it does not make the claim for mucus-only systems sometimes known as the Billings Ovulation Method or the Hilgers (Creighton) Ovulation Method.

The second purpose of this pamphlet is to demonstrate the unfairness used by some groups in their treatment of NFP and to call for fairness.

The Sympto-Thermal Method taught by the Couple to Couple League and most other teaching organizations uses the two natural signs of cervical mucus and the waking temperature plus certain information from the woman's own previous cycle history, and these three factors are used together in a cross-checking way. Users are generally taught about physical changes in the cervix for further corroboration, but such observations are usually not included in the rules.

A short word on terminology:

Phase I: pre-ovulation infertility starting with the first day of menstruation.
Phase II: the fertile time
Phase III: postovulation infertility

The term "Pearl rate" refers to a formula developed in the 1930s by Raymond Pearl to measure the relative effectiveness of various forms of birth control.