The Value of Rule B and Rule C

“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, 2002 CCL Convention.

In the stated effort to simplify the teaching, the learning, and the use of the NFP method to be taught by the Couple to Couple League, its current management has dropped some of CCL’s traditional rules in favor of what they now call one rule. I challenge that description because it looks like three rules to me. In my last blog I told why I think it is a mistake to abandon the sympto-thermal Rule K as an excellent way to determine the start of Phase Three, postovulation infertility. In this commentary, I want to address the possible abandonment of Rule B and Rule C as well as the concept of one rule for several situations.

Rule C

The “C” in Rule C stood for Cautious and Conservative. For most couples it was excessively conservative. As we stated in the Fourth Edition of The Art of Natural Family Planning, Rule C “requires BOTH three consecutive days of full thermal shift AND four days of drying-up.” I don’t know if it added anything by way of effectiveness to the other sympto-thermal rules, but it was an option that probably gave added confidence to couples with a very serious need to avoid pregnancy. A 3-day full thermal shift crosschecking four days of drying up presents a visually strong indication of postovulation infertility to anyone who is adequately informed.

Rule B

The “B” in Rule B stood for “Billings” in honor of his work, but it was a sympto-thermal rule. That meant that we wanted a sufficient temperature cross-check on the four days of drying-up. At first glance it appears that one of the rules or options in CCL’s new system is identical to Rule B, but that’s not the case. According to what we have heard, the temperature requirement in Rule B is stronger than the option in CCL’s new system.

Dr. Josef Roetzer

The management and staff at CCL claim that their new system is based on that of Dr. Josef Roetzer. That seems to be true. They also claim that the new system has only one rule and that it is therefore easier to teach, understand and use. I have not seen Dr. Roetzer making such claims. I admire his work that started in the Fifties and has continued into the present time. In Austria and Germany he has faced difficulties that may well be worse than what we have faced in the States. We are indebted to him and are grateful for whatever progress he has made in Europe and in the States as well.

One rule or three rules?

As I understand it, the basic Roetzer postovulation rule is a 3 + 3 rule: Phase Three starts on the evening of Peak-plus-3 crosschecked by three days of thermal shift, all above the low temperature level (LTL) with the last one at the High Temperature Level (HTL). That’s the basis for the Rule R (for Roetzer) we wrote into The Art of Natural Family Planning many years ago. Call that Rule One.

The confusion or contention starts when the pattern doesn’t meet both of those criteria. As I understand it from listening to CCL recordings, the Roetzer system has two more options.

In one of them, if the temps are above the LTL but not at the HTL, three days of a closed (not just closing) and firm cervix confirm the three days of drying-up and slightly elevated temps. Call that Rule Two.

A third alternative is used when Rule Two does not apply. In this alternative, once again Peak Day plus 3 is not confirmed by an adequate temperature rise. In this third situation, you wait until Peak Day plus 4. If on P + 4 there are four days of temps above the LTL by any amount, you can consider the evening of P + 4 the start of Phase Three. Again, that means that if on Peak + 4 you have four temps that are only one-tenth of one degree F above the LTL, you could apply this rule. Call that Rule Three.

The need to make distinctions

My concerns are twofold. One has to do with merchandising, the other with methodology.

When Dr. Prem and Sheila and I were the dominant influences at CCL, we made distinctions. When two situations were clearly different from one another, we gave them two different names. It seems to me that in the options above, there are three different situations. I am not at all persuaded that clarity is well served by saying they are all examples of the same rule but just different adaptations. In short, the “one-rule” language looks to me like mere merchandising. In the old CCL we had four sympto-thermal Phase Three rules that were clearly distinguished on the basis of the strength of the temperature pattern and the days of drying-up. We now call this the Kippley-Prem system to distinguish it from whatever CCL is doing or will do. In the K-P method or system, When the temperature pattern is very strong, fewer days of drying-up are needed as a crosscheck. We give these four situations four different labels to distinguish between them. I can still recall one of my college philosophy teachers telling us repeatedly, “bene docuit qui bene distinguit” — “he teaches well who distinguishes well.”

Thus I find it confusing to recognize three different situations and then to group them together and call it just one rule. This has nothing to do with the merits of any of the three rules, just the terminology.

My concern about methodology is illustrated by Figure 14.6 in the Fourth Edition of The Art of Natural Family Planning. It is an unplanned pregnancy chart that is confused by the fact that the couple did not follow the rules at either end of the fertile time. That is, the couple apparently ignored four of the standard Phase One practices, but they still stopped marital relations once the wife began recording mucus. The last marriage act in Phase One was on Day 8, mucus recording started on Day 9, and Peak Day was Day 12. On Days 14,15, and 16, the temperatures were all two-tenths of one degree F. above the LTL. Day 16 was Peak + 4 cross-checked by three days of temps above the LTL, but no temp had reached the HTL. The couple engaged in the marriage act on Day 16. They became pregnant. Did the pregnancy result from the marriage act on Day 8 or on Day 16? We simply do not know. Researchers have told us that ovulation sometimes occurs as early as Peak Day minus 3 and as late as Peak Day plus 3. Pregnancy could have resulted from the marriage act on Day 8 or Day 16 without taking any sort of small miracle to explain it.

The couple who submitted the chart in Fig. 14.6 knew that in their previous cycles the temperature shift was a clear four-tenths to six-tenths of one degree F above the LTL. They knew the temperature pattern by Day 16 was not like their previous experience, but they were not motivated to avoid pregnancy.

Rule B and Dr. Roetzer

In this case, the CCL Rule B would require them to wait two more days for a temperature reading at the HTL. We are told that Dr. Roetzer has had excellent experience with the rule calling for P + 4 crosschecked by a minimal rise in temps, but I have not seen any research published on it. I am also told that Dr. Roetzer tells couples to interpret the current cycle in terms of their previous cycle experience. If that were followed here, the couple would have waited two more days. So, the rule may not be so simple as it appears at first. Maybe the rule really is that you can use P + 4 with a mininimal rise in temps IF you have established from previous cycles that this is your common pattern. I would have no problem with that, and we addressed that situation in Figure 5.5 of the Fourth Edition of The Art of Natural Family Planning. So we will have to wait to see if CCL attaches the same qualifier that Dr. Roetzer apparently uses. (By the way, in the text for Figure 5.5 we note that we have never seen a shift of only two-tenths of one degree F above the LTL. That means a sustained thermal shift of the kind used for making decisions. Of course we have seen partial shifts on the way up to the high temperature level.)

Abandonment of Rule B and other CCL rules

And if that is the case, what sense is there in abandoning Rule B? If we understand what CCL is doing with its allegedly simplified, streamlined system (to use their marketing adjectives) it’s much ado about nothing or a lot of fuss over having less. It appears that CCL teachers are being asked to accept the loss of Rule C, the loss of Rule B, and the loss of Rule K with their clear distinctions. In return they are being asked to accept a basic rule that is essentially Rule R, another rule that is something like Rule B but lacks its high temperature requirement, another rule that accepts a low temp rise when there are three days of closed cervix to crosscheck the days of drying-up, and to call all of these a streamlined one-rule sytem.

The Kippley-Prem system

Our friends in the Czech Republic and Slovakia have been “competing” with the Roetzer system for some years. They have great respect for Dr. Roetzer and his teachers, but they have not been persuaded to adopt that system. They intend to keep what we now call the Kippley-Prem system. They are aware of a situation where some CCL-trained teachers were retrained in the Roetzer system and then wanted to return to the Kippley-Prem system. In our friends’ experience, couples who are acquainted with both systems are very happy with the clear distinctions and rules in the K-P system.

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

One Response to “The Value of Rule B and Rule C”

  1. CJ says:

    This doesn’t make sense to me. In your previous post, you went on at great length about the importance of minimizing abstinence. One day can make an enormous difference, you said. Here you seem to be saying that the couple from Figure 14.6 should have abstained for two more days. But the surprise pregnancy rate from P-4 (day 8 in this case) is much higher than the surprise pregnancy rate from P+4 (day 16). Two more days of abstinence doesn’t get you anywhere if you’ve already conceived.

    So which is it? Is minimizing abstinence more important, or is preserving the previous CCL system more important? Given the evidence for a P+4 mucus-only Phase III rule, I just don’t see why you’re making such a big deal about a slightly more relaxed thermal shift definition. Your case would be a lot stronger if this couple’s pregnancy had definitely resulted from intercourse on Day 16.

    John: If you check my previous post again, you will note that I argued for the earliest possible start of Phase Three based on the available evidence. In my opinion, the evidence on Day 16 in Figure 14.6 is insufficient for the couple who have a sufficiently serious reason to avoid pregnancy, especially in the light of what the couple had written about the strength of their previous thermal shifts.

    What is important is giving couples the knowledge-based freedom to determine the limits of the fertile time based on the available evidence. Well-taught teachers and students know that P + 4 without any temperature crosscheck does not give the assurance that P + 4 gives when it is crosschecked by a sufficient temperature rise. Without temperature readings, there is the possibility that ovulation did not occur and that it may occur in a few days. That’s a fundamental reason for taking the temperature readings which are a key part of the sympto-thermal method. With readings that do not constitute a sufficient temperature rise, there is the same possibility, especially if a woman’s previous cycle history showed very sharp temperature rises to crosscheck the drying-up of the mucus. When the evidence is unclear, the couple who have a sufficiently serious reason to postpone pregnancy are best advised to wait until the evidence is clear. My point about Rule K in the previous post is that sometimes the temperature-based evidence is sufficiently clear on P + 2.