Abandonment of Rule K

“In my 30 years in Brazil, I saw many promising apostolates rise—and then fall as they abandoned the charisms of their founders.” –Bishop Karl Jozef Romer, Pontifical Council for the Family.

One of the three principal charisms that Sheila and I brought to the Couple to Couple League was the charism of choice. By the time we met Dr. Konald A. Prem in 1971 we had used all three signs of fertility and infertility. From a book by the Kanabys, from an article by Dr. Prem, and through correspondence with two women who had lots of personal experience with the mucus and cervix signs of fertility during breastfeeding amenorrhea, we had learned all the signs well before we started CCL. All of that was helpful and oriented us toward freedom of choice among morally good alternatives. With regard to marital chastity, there was only one morally good choice–don’t engage in unnatural forms of birth control. With regard to breastfeeding, the evidence was clear that breastfeeding was best for both baby and mother and that ecological breastfeeding had the effect of naturally postponing the return of fertility. Thus, in our teaching program, we could not teach “choice” on those two matters. But with a system of fertility awareness, there was no moral imperative to teach one system to the exclusion of the others. So we opted to let individual couples choose which signs they wanted to use. We preferred using the signs in a crosschecking way, but we taught the signs in such a way that they could be used independently. Our pledge was to support the choice of the couple within the limits of the sign or signs they had chosen to use.

It is therefore disappointing to learn that the current management of CCL is abandoning two of the crosschecking Phase Three rules we developed. At first, we were heavily influenced by the mucus-only rule that said Phase Three starts on the evening of Peak Day plus four, so that was combined with the temperature requirement of three days of well elevated temperatures. As we became more aware of the temperature-only research, we realized that it had achieved excellent results. The well known biostatistician Christopher Tietze had said that the three-day temperature-only system for the start of Phase Three was as effective as surgical sterilization, and that was without any reference to mucus.

I am aware of two temperature-only studies that support the three-day rule used in Rule K. Thomas W. McGovern, M.D., wrote the effectiveness chapter in the Fourth Edition of The Art of Natural Family Planning, and this is what he said on pages 149-150 about these studies.

Regarding the French study by B. Vincent et al., Dr. McGovern wrote: “In 17,496 cycles of using a temperature-only rule to determine the start of Phase III, there was only one clear perfect-use pregnancy. That yields a Pearl Index of .07 [that is, an effectiveness rate of 99.93 percent]. One statistical problem is that couples used either three or four days of thermal shift. Although this 1967 study does not meet today’s higher standards, it strongly supports the CCL four-day temperature-only rule and Rule K which calls for three days of full thermal shift cross-checked by at least two days of drying-up past Peak Day.”

Regarding the German 1967 study by Dr. G. K. Doering, Dr. McGovern wrote: “Phase III was determined by a three-day temperature-only rule. The 307 couples having relations only in Phase III contributed a total of 11,352 cycles and experienced 8 unplanned pregnancies, yielding a user-effectiveness Pearl Index of 0.8 [99.2 percent effectiveness rate]. Of those 8 pregnancies, ‘one was due to misinterpretation of a temperature rise caused by a cold, five were pure patient errors, i.e., intercourse during the fertile phase, and two had incomplete temperature records’.”

Dr. McGovern continued regarding the Doering study: “Phase I plus Phase III was used by 689 couples for 48,214 cycles. They experienced 125 unplanned pregnancies, yielding a user-effectiveness Pearl Index of 3.1 [a 96.9 percent user-effectiveness rate]. Among those 125 pregnancies, 6 were from relations on the second day of upward thermal shift. Of the rest, ’12 [couples] had misinterpreted temperature rises from colds, 13 conceived toward the end of the “safe” postmenstrual period, 56 were patient errors, and 38 had kept incomplete records…Conception never occurred on the third day of hyperthermia [well elevated temperatures]‘.”

“Again, this study does not meet today’s higher standards. Rather obviously, the couples were in the study for more than the one-year limit currently required and it is not clear that all the couples using Phase I regularly used it to the limits of the Doering rule. Nevertheless, it continues to support all the temperature-based Phase III rules, and it is the basis of the Doering Phase I rule now being taught by CCL.”

You may wonder how and why we developed Rule K. We had questions about patterns in which the temperature rose before Peak Day. Sometimes we would see four or five days of well elevated temps by the time we saw P + 4. Since it had been well established that women were almost always infertile by the evening of the third day of well elevated temps, we wondered whether couples should have to wait another day or two for confirmation from the mucus sign. We discussed this with Dr. Prem, and he suggested that we should call for at least two days of drying-up past Peak Day to insure that the high temps were not caused by something other than postovulation hormones. That’s how Rule K came into existence. That is, according to Rule K, Phase Three starts on the evening of the third day of full thermal shift cross-checked by two (or 3) days of drying-up past Peak Day. (Full thermal shift means three consecutive days with waking temperatures at least four-tenths of one degree F. above the low temperature level.)

As we heard CCL’s new system explained, we learned that the basis for Phase Three is Peak-Day-plus-three as in Dr. Josef Roetzer’s system. Therefore, Rule K has been abandoned. We are told that the new rules were compared with the old rules on lots of charts in CCL’s files, and the new rules yield the same day or differ by only one day. Rather obviously, when the pattern is appropriate, Rule K with its Peak-Day-plus-2 crosscheck will always yield a start of Phase Three one day earlier than a Peak-Day-plus-3 rule.

We have heard the claims about how great it is going to be to have only one Phase Three rule, how simple it will be to teach and to use. Really? Is it really simpler to use a system that unnecessarily adds a day of abstinence? Sometimes one day can make a big difference. Consider asking your students this question: “Would you like to take ten minutes to learn a rule that sometimes shortens abstinence by one day (or even two days in some cases when compared with mucus-only rules)?” What do you think they will say? Is your purpose in teaching to make things as easy as possible for you or to make the practice of chaste NFP as easy as possible for your students?

This poses an ethical question for teachers whom I will now address. Many of you experienced teachers have used Rule K. You have taught it for years. You know the temp-only work behind it. You know it works as well as anything else. If you are presented with a chart by phone or in person that shows that the couple are in Phase Three that evening by Rule K, do you tell them that they need to wait one more day to comply with the new system? What if tonight is the last night they will be together for a week because of travel that starts tomorrow? What if the couple confides that they have been struggling with chaste abstinence and that a day makes a difference to them? What if the husband is shipping out tomorrow for six months in Iraq? Is your responsibility to be faithful to a system or to support the couple by giving them the information they need to arrive at the earliest possible interpretation of Phase Three that is consistent with the evidence? In my opinion, you are ethically and professionally obliged to tell them about Rule K. Of course, your situation is complicated because in the new system you will have hid this rule from them.

If the scenario of holding back valuable information does not appeal to you, you need to let the CCL Board of Directors hear from you—-and sooner than later.

More next week, God willing.

John F. Kippley
Author, Sex and the Marriage Covenant: A Basis for Morality (Ignatius, 2005)
Natural Family Planning: The Question-Answer Book, a short, free, downloadable e-book available at the home page of www.NFPandmore.org.

Comments are closed.