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Comparison of symptothermal methods: TCOYF versus SYMPTO

Analysis of significant differences between Toni Weschler’s Manual Taking Charge of Your Fertility (TCOYF, the manual, its related app OvaGraph) and sympto (synthesis of Sensiplan/Rötzer et al.) with notes on the Kindara App.


Dr. Harri Wettstein, Secretary of SymptoTherm Foundation, Switzerland


sympto (based on Sensiplan/Rötzer), (the German app based exclusively on Sensiplan), and a number of American apps have already been contrasted in our 2013 app comparison study (in French), and in the 2014 study (in English), see The Complete Symptothermal Guide can be downloaded  on

The 2015 edition of TCOYF still combines two diverging methods (adopted also by Kindara in its non-interpretive app), each based on opposing paradigms: the Billings Ovulation Method (“Billings” in the text) and the symptothermal systems. This fusion gives rise to a basic methodological incoherence, which we will analyze in this paper.

Knowledge of basic concepts such as Peak day, base or cover line, and temperature rise is presupposed here. ‘Elixir’ is the term used by sympto for cervical mucus or fluid.

Paradigm confusion

For the early cycle days, the Billings paradigm, implemented by Toni Weschler, but never discussed by NFP specialists so far, relies on the “BIP”: the Basic Infertile Pattern. The BIP in the beginning of a cycle classifies a woman as basically infertile. She waits for the appearance of fertile signs as her cycle progresses to halt the BIP and open her fertile phase. This fertile phase ends 4 days after Peak day where she begins her (postovulatory) infertile phase. The symptothermal world presupposes just the contrary. At the start of a cycle, a woman is always considered potentially fertile, even during menses, unless the following conditions have been fulfilled: if menses follow a qualified luteal (postovulatory/infertile) phase (yellow on sympto), these same menses trigger a new cycle, of which the first few days are definitely infertile. This is a radical paradigm shift implemented by the symptothermal methods!

A woman verifies her BIP on a daily basis allowing her to prolong the infertile, preovulatory phase (pink on sympto) according to her personal BIP until cycle day 8, 10 or even beyond. The promotional statements of the Billings Ovulation Method thus claim a woman “gains” infertile days, making the method seemingly more attractive. But are these “gained” days really infertile? Not necessarily! The symptothermal paradigm rests firmly on the most scientific credentials when it comes to judging the effectiveness of the method. In the symptothermal paradigm, two criteria must be met to confirm preovulatory infertility: neither elixir nor moist sensation is to be present and the (temperature-rise-related) so-called Döring-Rötzer Day (D-day) must not yet have passed. D-day is the earliest temperature rise of at least 12 preceding cycles (see The Complete Symptothermal Guide, p. 27-28). The BIP system, since it does not consider temperatures, cannot use this crosscheck to determine the end of the infertile (preovulatory) phase. It claims that a woman can identify her infertility (BIP) in her first cycle with just one criterion as long as, and this is crucial, her cycle presents an easy pattern. Are the Billings observations really so straightforward and easy? No: As soon as she has any kind of continual vaginal discharge she must observe at least 3 consecutive cycles to figure out her own BIP. The rule is: if this discharge shows the same pattern in every cycle, it is categorized as her BIP and she can consider herself infertile; whenever the pattern changes, fertility must be assumed from that day onwards.

There is a crucial disadvantage of the BIP concept: a couple is instructed to have (unprotected) sexual intercourse on alternating evenings only because semen might confound elixir the day after intercourse. In the symptothermal systems there are no such restrictions: sexual intercourse is possible every infertile day. In other words: the higher number of infertile (preovulatory) days you might gain with Billings-like methods must be divided by a factor of 2 because intercourse is only permitted every other day! If a woman has 6 (preovulatory) infertile days in a symptothermal system, she has only 3 in Billings! Kindara incorporates yet another pitfall: it indicates that the first three days of menses are infertile at any rate; for the symptothermal method, this is only true for real menses, not for intermenstrual bleeding episodes. This difference is significant as intermenstrual bleeding can mask fertile days!

In the sympto icon language, the BIP of the TCOYF system is expressed by a black horizontal bar (“seen nothing”) or by the little sun icon (dry feeling, possibly a tingling sensation). This might last for 10 days or even longer and is divided by 2 for sexual activity in TCOYF. On sympto (Sensiplan/Rötzer), the result of this observation is identical during the infertile days before ovulation without, however, being divided by 2 for sexual activity! Even though these two signs of infertility are identical in both schemata, the Billings and the symptothermal, sympto opens a woman’s potentially fertile phase for safety reasons on her D-day.

The TCOYF system does not challenge the BIP throughout the preovulatory days as long as a woman makes the same observations day after day. The danger is that a woman might already be in her fertile phase without noticing because frequently the signs of elixir or moist sensation have not yet surfaced. So she may enter the black bar icon in her chart confirming the infertile state, “seen nothing”, not realizing that her fertile window has opened and that she is in fact fertile! On sympto (and all genuine symptothermal systems) she has to wait out her first 12 cycles before identifying eventually more preovulatory infertile (rose on sympto) days. New charters have 5 infertile days unless they feel or see a fertile sign earlier. However: an expert charter on sympto can have unprotected intercourse in the beginning of her potential fertile phase (blue on sympto) if she has observed and enters 2 signs: the black bar for no elixir and the little sun for dry sensation or the icon for “closed cervix”. This is a variation of a crosscheck. In this case, the woman knows that she is taking a calculated, yet, very low risk: she is not extending her BIP. The difference seems minor but it is key for the effectiveness and for understanding the paradigm.

General considerations

A principle which is unchallenged in all systems is this: if a woman observes a fertile sign within the preovulatory infertile phase (on sympto the blue drop or the blue stick during the rose days) she must consider herself as fertile from that day onwards until Peak day and the following crosscheck with her temperatures which will close her fertile window. On Billings, as there are no temperatures, there is no crosscheck: a woman usually enters her infertile state on the fourth day after Peak day (if identified correctly, a problem we cannot discuss here).

Let’s have a closer look at a tricky scenario: a woman sees vaginal discharge immediately after her menses come to an end. If this observation has been confirmed (over 3 cycles) as her BIP, she must enter a special symbol in her chart. On sympto, she immediately carries out the water glass test to determine the type of discharge. If it is not identified as elixir or moistness (see The Complete Symptothermal Guide, p. 44), i. e. not to be labeled with a fertile icon, the woman charting on sympto has to enter the black bar and use the Remarks field to describe her discharge. These days are considered infertile. There is no icon on sympto for infertile discharge (except the yellow cloud icon representing progesterone activity after Peak day which is an elixir classification unique to sympto). A sympto user always carries out the water glass test whenever she is in doubt about any fluid she finds, especially also in the case of semen that may be present from intercourse the night prior. This test clearly differentiates elixir from all other fluids.

A critical difference between TCOYF/Kindara and sympto concerns the early or late temperature rise (“early” or “late” compared to Peak day): sympto displays all valid Peak day/temperature combinations in its Da Vinci Code (see The Complete Symptothermal Guide, p. 52): the different variations are fully explained; sympto correlates the occurrence of Peak day with the temperature rise. The Da Vinci Code is an educational pictogram displaying the ways sympto works through its algorithms. In TCOYF/Kindara there is no discussion of early temperature rises on Peak day or before although these situations are clearly documented by the scientific Rötzer and Sensiplan studies. There is another crucial point missing: TCOYF permits only one or two days of late temperature rises! What if the temperature rises at day 3 or even 4 after Peak day, which is tolerated by Rötzer/Sensiplan/sympto? TCOYF/Kindara do not explain how these cases are handled. How can the TCOYF/Kindara counselor know what to tell her client in these situations?

Similar to sympto, TCOYF’s app OvaGraph offers interpretation of charts but Kindara does not. In spite of its “analytics” feature that will draw a cover line it fails to execute the critical symptothermal crosscheck. In the American app comparison study where sympto occupies the first place of all symptothermal apps (FACTS, 2016 : to be downloaded on, OvaGraph sits at place 8. I do not know the details of this weak ranking but presumably it is because of the imprecise opening margin of the fertile window: days displayed as infertile although fertile and referred to in the literature as “false negatives”. These days hamper the effectiveness of the interpretation.

Some vital app differences

Unlike sympto, OvaGraph is not suggested as an alternative for natural contraception and TCOYF explicitly warns readers not to rely on any apps for contraceptive purposes. She refers to the need for proper instruction in the method as her reason, completely ignoring our educational approach. Based on our app studies, apps well suited for natural contraception do exist but they are the exception! As long as NFP specialists continue to ignore this fact, newcomers to the method are forced to choose their app in an environment that misinforms them.

In the OvaGraph app, a woman cannot dialogue with her counselor, she can only post her cycle charts in an internal forum. The idea is that a user will purchase the voluminous TCOYF manual and find a specialist independently to counsel her. The app is not an educational device; it is at best an auxiliary motivator.

In the TCOYF manual, there are no comparative app studies mentioned although author Toni Weschler is aware of our SymptoTherm Foundation ever since the time of Bioself, the LadyComp-like fertility indicator (2002). The TCOYF manual fails to show how the algorithm of OvaGraph fits in with the TCOYF method. The app just refers to the book without any further transparency. We would like to know, for example, how the OvaGraph app integrates the cervix exam with Peak Day.

In the Complete Symptothermal Guide (p. 86 -88), sympto reveals its solution for cervix exam interpretations that are in line with Sensiplan and Rötzer. The cervix exam interpretation is indicated when elixir observations remain confusing. sympto integrates the specific cervix exam approach by Sensiplan, as well as the typical Billings Peak day identification (p. 79): slippery, lubricative without visible elixir, followed the next day by dry or moist sensation.

Temperature rise and temperature laws of sympto

In her new 2015 edition of TCOYF, Toni Weschler admits that the third temperature rise may also happen already three days after Peak day. In her former edition, it had to be on day 4 or later but never earlier! According to her, the third higher temperature does not need to be 0.2 °C (0.4 °F) above the cover line, but only 0.15 °C (0.3 °F) above it, which is too low compared to the Rötzer/Sensiplan/sympto standard. It is possible that in the American study quoted above this insufficiently high third temperature may also have caused false negative days in the postovulatory phase, i.e. days displayed as infertile although they are still fertile. sympto acknowledges that the last decisive temperature may be less than 0.2 °C (0.4 °F) above the cover line as long as it is the 4th day of the temperature rise (and after Peak day), including also one questionable day according to the basic law of sympto: the second or third day of the temperature rise can be missing or fall below the cover line.

TCOYF’s and Kindara’s Peak day rule requires women to wait until the evening of the 4th day after Peak day for infertility to start as does the Billings Ovulation Method. This rule holds even if the third higher temperature is high enough to close the fertile window already! This 4th day does not make sense at all as soon as the system has correct temperature rise laws. In all symptothermal systems, the Peak day rule always covers a waiting period of three days, not more, provided the temperature rise is accurate.

Elixir: a confusing category mistake

Like Sensiplan/Rötzer/sympto, TCOYF and recently also Kindara, clearly separate between the inner sensation, on the labia or the bodily feeling, and the (external) observation by touch or by sight. But labeling it “sticky” is confusing because this description is used for both inner and external observation, whereas on sympto “sticky” (Sensiplan and Rötzer) refers to external observation exclusively. This confusion stems from the Billings and related schools such as the Canadian school of the Justisse method.

The sticky feeling which is supposed to characterize inner sensation is a language abuse, an embarrassing “category mistake”, which should be banned. It is regrettable that women do not discuss this category mistake in their forums. The vaginal sensation can be moist, wet, dry or tingling, but it cannot be sticky like a shirt on sweaty skin because being able to identify a “sticky” sensation requires sporadic contact of surfaces!

Breastfeeding Program

In sympto’s Breastfeeding Program, which is still unique to sympto, the Billings Peak day rule (Peak plus 4 days) and the BIP make sense: After giving birth and during breastfeeding, the cycle is basically infertile; in the wake of her exclusive breastfeeding a nursing mother will spot the first fertile signs only months after the birth of her baby. There is no paradigm confusion, as this program does not require temperatures. Breastfeeding mothers very often have continual discharge that does not vary; they show a typical BIP pattern for which there are no signs on sympto because this pattern does not express fertility; there is only the Remarks field to leave a short comment. In this situation, the sympto user enters the bar, infertile, plus sometimes a comment to document her BIP. The breastfeeding Peak day rule of sympto also requires the elapse of 4 days after Peak day similar to Billings until infertility can be indicated. However, in order to remain consistent, on sympto infertility begins in the evening of the fourth day whereas in Billings it begins in the morning of the fourth day.

There is no breastfeeding program either on OvaGraph or, as of now, any other existing apps. In the TCOYF manual the corresponding explanations remain confusing: they are not based on the BIP as they should be. For the user, the big challenge on sympto’s breastfeeding program is a) to determine correctly the BIP (this challenge is constant on Billings), and b) resist NFP encouragements to resume useless and demotivating temperature recordings! sympto has a similar program for peri-menopause. As fertility is significantly lower so the Peak day rule indicates infertility in the evening of the third day already, not the fourth day as for the breastfeeding program.

Free choice fallacies and different options on sympto

The American app comparison study quoted above compares Billings-like apps with symptothermal apps and even with the Standard Days method apps (old rhythm methods). It compares what is not comparable to determine effectiveness. It is simply not true that more effective methods are more demanding or require more discipline than less effective ones when it comes to comparing Billings and the symptothermal paradigm. Of course, any Standard Days method will be easier to follow as there are practically no observations to enter, but its effectiveness resembles Russian roulette. It is a shame that the WHO popularizes a Standard Days method app in Africa within very expensive family planning projects; the WHO is not interested at this time in the symptothermal method as it was in the nineties. This is another story.

The point we want to emphasize is that the symptothermal systems should not be rigid when it comes to user choice; they should allow a Billings-like subroutine or a sole temperature interpretation, which fits in the overall picture. These two subroutines exist only on sympto. A woman can ease into charting on sympto with just temperature recordings: maybe because she has never heard of elixir or because synthetic hormones have dried out her cervical crypts and she cannot see anything without cervix exam. If she is trying to conceive, for example, she can just spot her Peak day by entering elixir observations. Both techniques are a first step toward learning symptothermal observation. As soon as she is ready to delve deeper into her observations to make them fully symptothermal she will be able to identify her most fertile days and also practice natural contraception. After several months or years, as an expert sympto charter, she can drop many of the temperature recordings. Only sympto, which is the synthesis of the symptothermal methods, provides these educational subroutines.


TCOYF has existed since 1995 and its corresponding app OvaGraph for about 6 years. Why has there never been any major breakthrough in the U.S. regarding Fertility Awareness Based Methods (FABM)? Why do women accept the misinformation disseminated by Public Health, sex educators, quasi-symptothermal apps and physicians? My answer is this: Women remain cycle-illiterate because FABM specialists don’t fight for optimizing the symptothermal method. Unlike sympto, they ignore this important women’s cause and care only about their own projects or remain captive in their schools. There are however good initiatives like FACTS or Natrualwomanhood which promote FABM as a whole. The problem is that this kind of promotion does not point out the methodological differences and thus does not really help couples to make their informed choice.

When it comes to demonstrating the effectiveness of the symptothermal methods, Americans refer to the German study of 2007 (downloadable on They wrongly refer to this study, as their apps have not fully integrated the Sensiplan standards. These standards are visible only on sympto and, and in the Californian app Lily (which is without web access, however). Until now, the old traditional schools like Sensiplan, Rötzer and NWFS (the American Rötzer version) as well as TCOYF deny the usefulness of interpretative apps for entirely misleading and dogmatic reasons that are discussed in The Complete Symptothermal Guide, p. 10.

We endorse genuine symptothermal schools such as CCL, NWFS, Sensiplan, Rötzer or sympto that employ the crosscheck of elixir and temperature to determine the opening and closing of the fertile window. Quasi-symptothermal systems such as TCOYF or the French CLER do not execute this crosscheck to open the fertile phase. This is one of the reasons for their lower effectiveness. Some Italian and other systems apply a crosscheck based on unreliable old rhythm methods. It is preferable to have a non-interpretative app like Kindara than an interpretative app that displays too many false negative days like OvaGraph: days on which intercourse can lead to unwanted pregnancies. The future however belongs to interpretative apps like, CyclePro (CCL) and sympto. These apps have been thoroughly studied by the SymptoTherm Foundation in 2013 and 2014 (see in cooperation with the Federal Swiss Polytechnic in Lausanne; the studies have been published in a Swiss medical journal. The conclusion is that there are several sound reasons for sympto to be the first choice for any kind of fertility situation.

Realizing that the most popular fertility-tracking app in the States, Glow, has no symptothermal foundation, we urge women to discover that “predicting” apps such as Glow etc. are all quasi-symptothermal!

Toni Weschler wrongly maintains that apps should not be used for contraception. In reality, some apps can be relied upon for contraceptive purposes just as soon as the user has achieved competence in the real method with or without a counselor, online or in person.

Harri Wettstein, SymptoTherm Foundation, 1132 Lully, Switzerland, July 2017.

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