Determine Fertile days with the Symptothermal Method

Determine Fertile Days

Determine Fertile Days with Symptothermal Method

Determine Fertile days with the Symptothermal Method – How does it work? Use the signs of ovulation mucus & temperature to get pregnant faster.

As a fertility coach, I keep being asked how to determine your fertile days to get pregnant faster. The Symptothermal Method is the best scientifically tested method to determine the fertile days and to limit ovulation exactly to a few days. In clinical trials, it has been shown that couples who determine their fertile days with the Symptothermal Method get pregnant faster. I myself have get pregnant twice with the Symptothermal Method despite Hashimoto and luteal Insufficiency and would like to share my experiences with you in this article.

What is the Symptothermal Method (NFP)?

NFP is an abbreviation and stands for Natural Family Planning/ the Symptothermal Method. The Symptothermal Method actually summarizes a number of methods that use the observation of ovulation signs such as basal body temperature, mucus and cervix to determine the fertile days. The most well-known methods of Natural Family Planning are the temperature method, cervical mucus method and the Symptothermal Method. The Symptothermal Method is simply called “NFP” in German-speaking countries by most people. The Symptothermal Method is by far the best studied Natural Family Planning method and – historically – originated from the cervical mucus method (Sympto) and the temperature method (thermal) and thus represents its natural evolution. In this article too, when I write NFP in the future, I would like to refer to the Symptothermal Method (NFP), as it has become so naturalized.

Which Natural Family Planning Method is the best?

I am often asked which Natural Family Planning (NFP) is the best to determine the fertile days? The answer here is very clear, the Symptothermal Method and this has a main reason. Both the Cervical mucus and Temperature methods ONLY use a single check to determine the fertile days. Consequently, the temperature method and cervical mucus method are more susceptible to interference compared to the Symptothermal Method. For example, if the temperature or mucus is disturbed by a disease such as fever or vaginal infection, you may no longer be able to determine the fertile days in the respective cycle. For this reason, the Symptothermal Method always uses two ovulation signs, namely a combination of basal body temperature and mucus or basal body temperature and cervix to determine the fertile days. This Double Check leads to simpler, more flexible method rules that lead to a more accurate and reliable determination of the fertile days. In studies, women who use the Symptothermal Method can determine their fertile days in about 94.5% of cycles. In the Temperature Method, due to the strict method rules for temperature rise and susceptibility to interference with the temperature, the fertile days can be determined in only 52% of the cycles. This means that in the temperature method you can determine your fertile days in just under half of the cycles. The cervical mucus method has relatively complex method rules and is very inaccurate compared to the Symptothermal Method (NFP). This is mainly because the mucus cannot reveal whether an ovulation actually took place in the cycle. Thus, the Symptothermal Method (NFP) combines all the advantages of the temperature method and cervical mucus method in one method. The Symptothermal Method is therefore applicable to almost all women, among others, even for irregular cycles, shift work, PCO cycles and others. For this reason, it can be said clearly that the Symptothermal Method is the best NFP method to determine the fertile days. The specified studies can be read in the book NFP Today, from the Natural Fertility Section.

Determine Fertile days with the Symptothermal Method – How does it work?

Fertile Days in Menstrual Cycle

The fertile period consists of the survivability of sperm (5 days) and the 1 day on which the egg is fertilised

In biology lessons, we learned that in order to get pregnant, sperm must come together with the egg. The egg can remain fertile in the woman’s body for only about 12 to 18 hours. The sperm can remain fertile in the woman’s body, thanks in part to the cervical mucus that nourishes them, for about 3 to 5 days and wait for ovulation. This results in a biologically fertile period, which can be determined by means of body observation, the ovulation signs mucus and temperature, as well as temperature and cervix. In practice, therefore, women measure their basal body temperature in the morning and document their cervical mucus in the course of the day in the toilet and enter this course into a cycle sheet or a suitable NFP app. They can then use cycle documentation according to fixed and scientifically tested Symptothermal Method rules to determine the fertile and infertile days in the cycle. How to correctly observe, document and of course, the rules of the body signs, can be found in my Book “WHEN AM I FERTILE?“. There you will also find exercise cycles with solutions where you can test whether you can correctly determine the fertile days. Specifically for Christmas, there is a special Christmas cycle sheet for the book with great design, so the registration is even more fun!

Determining Fertile Days – Is There a Device?

Many women nowadays are increasingly looking for an all-in-one device to determine the fertile days. So far, these devices are not very well studied. In the only relevant study by “Stiftung Warentest“ from the year 2000, the Symptothermal Method has deprecated all common computers from the market. The devices showed strong deviations from the real fertile days, which were determined by medical methods. The conclusion of the study was therefore correct: Pencil beats cycle computers. Clearly, no one knows how good the devices really are, anyone looking for pregnancy rates or studies is usually disappointed. The fertility algorithms of the computers are a trade secret for understandable reasons. The study found the tendency for temperature computers to be more reliable than LH computers when considering the determination of fertile days. Likewise, the study found that mucus computers are not suitable – for this reason, it is not surprising why these have now been withdrawn from the market. The Symptothermal Method has not only been convincing in this study – several studies have shown that the pregnancy rate can be increased by the Symptothermal Method. From my point of view, therefore, it is right today, as then, that you do not need a cycle computer. The only device you really need to determine your fertile days is a digital Basal Thermometer with two Decimal Places to measure your basal temperature over the cycle.

Determining Fertile Days with an LH Test

Many women use LH tests to determine their fertile days. The basic idea of an LH test is very simple – just before ovulation, the luteinizing hormone (LH) rises sharply, and thus a sharp increase in LH concentration is an ovulation sign for the most fertile days. Unfortunately, LH tests are not very reliable, because the luteinizing hormone can fluctuate greatly during the course of the day and also during the cycle. Similarly, the basic level of women is different, which makes evaluation very difficult with simple tests. It is not uncommon to display negative, even though you’re actually in the most fertile period. Likewise, it’s possible that they’re showing positive, though you might not have ovulation at all. Whether you have ovulation, you can’t tell with an LH test, as I explained in detail in my LH Test Experiment. Thus, while LH tests are better than a fertility calculator, they are too inaccurate compared to the Symptothermal Method.

Fertile days determination during Irregular cycles

As mentioned above, the Symptothermal Method (NFP) is applicable to all women who have a cycle, so can observe menstruation in the cycle. The natural cycle fluctuates between 23 and 35 days in most women anyway, making it anything but regular. However, the Symptothermal Method is also applicable for short cycles under 20 days or even for long cycles over 100 days. This applies in particular to shift work, where in studies, about 90% of the cycles determined the fertile days (Rosmus T 1992). The Symptothermal Method is also very suitable for women with PCO who may have very long cycles. Contrary to cycle computers, which have problems with long cycle lengths and irregular cycles, especially after discontinuation of contraceptive pills, the Symptothermal Method (NFP) is also easily applicable in women with such irregular cycles. There are even special Symptothermal Method rules after discontinuing hormonal contraception for determining the fertile days which are also explained in our book.

How fast does one get pregnant with the Symptothermal Method?

pregnancy rate fertility awareness

C Gnoth et. al. Hum Reprod. 2003 Sep;18(9):1959-66.

In the end, all the women I work with always ask the same question: How fast does a woman get pregnant with the Symptothermal Method? Are there statistics here? Yes, there are! With the Symptothermal Method, about 81% of women became pregnant within 6 months and a staggering 92% after 12 months in a 2003 Study. By comparison, without a method, only about 60% of women get pregnant within 6 months and about 85% within 12 months. So the Symptothermal Method can demonstrably increase the pregnancy rate. Even after a long wait, at an advanced age from 35+, i.e. in difficult cases, the Symptothermal Method was able to convince in Studies and significantly increase the pregnancy rate. There is no 100% pregnancy guarantee, but statistically it is scientifically proven that the Symptothermal Method can increase pregnancy rate.


The Symptothermal Method (NFP) is currently the best scientifically tested NFP method for determining fertile days and limiting ovulation to a few days. It has been shown in several studies that application of the Symptothermal Method to determine the fertile days in the cycle can boost pregnancy rates. In the same way, the Symptothermal Method is also easily applicable even for irregular cycles, especially for shiftwork, after discontinuation of contraceptive pills or for cycle characteristics such as PCOS etc.! The Symptothermal Method is much more effective and precise than cycle computers or other devices that determine the fertile days, as well as very inexpensive. In principle, all you need is a book to learn the Symptothermal Method rules, a thermometer to measure temperature, and a cycle chart, or an app for documenting ovulation signs to apply the method. I wish you all the best on your quest for your desired child!
Wishing you wonderful fertile days…



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