SymptoThermal Method

Natural birth regulation


. Introduction

. Physiological cycle

. Sign of mucus

. Sign of temperature

. Additional sign: cervix

. Beginning of the cycle - Peak day - Union - Comment

. Interpretation

. Automatic analysis

. Special cases


SymptoThermal Method is a free application for iPhone available on the App Store, that helps you to use natural birth regulation. This is a method of self-observation which allows:

  • . Every young girl and woman to find out more and learn about their body and their cycle.
  • . You to determine the beginning and the end of the fertility phase, based on the signs of mucus and temperature.
  • . Any couple to have a dialogue based on trust and tenderness, to make the responsible choice to welcome a new child or to space births, or to avoid pregnancy.

Know your fertility, not only to better explore your femininity, but also increases your sense of responsibility. Self-observation methods, experienced within the couple are a source of greater dialogue, greater confidence and greater love.

Explanations of this help do not answer all individual cases. For proper use of this symptothermal method, it's important to contact and be trained by a monitor* in your country.

* UK :

Physiological cycle

We distinguish three consecutive phases between the beginning of the cycle to the following cycle:

Latency period: Infertile period

During menstruation and after menstruation until the appearance of the mucus.

  • . The pituitary gland and ovaries are at rest.
  • . No mucus.
  • . Low base temperature.
  • . Cervix low, closed with mucus plug.

Please note that in the case of a short cycle from first day until ovulation, the secretion of mucus may begin during menstruation and thus be hidden by menstruation.

Fertile period

  • This is the pre-ovulatory and ovulatory phase.
  • . The pituitary gland awakens and stimulates the ovaries. Increased estrogen.
  • . Appearance of the mucus which is more fluid until ovulation.
  • . The temperature is still low.
  • . The cervix stands up, opens and softens.

At the time of ovulation, it is possible to feel a little ovarian pain or little bleeding.

Possible second ovulation only 12 to 24 hours after the first.

Post-ovulatory period: Infertile period

  • . The mucus diminishes or disappears.
  • . The temperature increases by at least 0.3°C or 0.6°F and remains stable: this is the offset temperature (effect of progesterone).
  • . The cervix is lowered, closes, becomes hard.

After the 3rd day in the morning with a high and stable temperature, the couple is infertile.

Cycle times, the egg and spermatozoons:

Cycle time: duration between the first day of cycle to ovulation is variable. The part between ovulation and the end of the cycle lasts about 12 to 16 days.

The lifespan of an egg is 24hrs.

Spermatozoons can live up to 5 days in the presence of mucus.

Sign of mucus

Purpose: The feeling of humidity or mucus observation determines the start of the fertile period.Method

  • . sensation:
  • This is what women experience during the day in the vulva: dry, humid, wet, lubricated.

  • . observation:
  • This is what women observe in the vulva passing her fingers or toilet paper over the vulva: thick mucus, creamy mucus, egg white mucus.

  • . In practice :
  • Women note 3 times a day sensations and their observations. In the evening, after selecting the date, they note on SymptoThermal Method the most important signs of fertility.

  • Sometimes we can see the presence of vaginal secretions. This is different to mucus because women aren't fertile in the presence of vaginal secretions alone. At the beginning, you need the help of a monitor to recognize this difference.

Sign of temperature

Purpose: To determine the end of the fertile phase after the third day in the morning high and stable temperature.


The temperature is taken upon waking up, before getting up, and if breast feeding before feeding. If you get up at night, you need to rest for an hour to get the right temperature.

The temperature can be taken by rectal, vaginal (3 minutes) or oral (5 minutes).

Always use the same thermometer if possible gallium, with graduations hundredth. You can use a thermometer in Celsius or Fahrenheit but do not change during the same cycle because otherwise this can lead to misinterpretation.

After selecting the date, note on SymptoThermal Method the temperature.

If the temperature was taken more than an hour after the usual time taken, specify in the comments box to help interpretation. Ex: + 2hrs.

Determination of 3rd high and stable temperature day

After ovulation, the base body temperature rises a few tenths of degrees and stays high and stable until the following menstruation or remains high in pregnancy. The observation of a high and stable temperature signifies that ovulation has occurred and the woman has become infertile.

Locate the offset temperature:

  • Not too fast, not more than 0.4°C or 0.8°F overnight.
  • Not too early in the cycle: rarely before the 10th day.

Identify 3 consecutive points:

  • . High: 3 points at or above the upper line (red line).
  • . Stable: It should not be more than 0.1°C or 0.2°F difference between the first and third point. The second point can be 0.2°C or 0.4°F different from the first day.

In practice on SymptoThermal Method

  • . Last low point

We must identify the last low point of temperature before the offset temperature. It is noted retrospectively by selecting "Yes" in "Last low point". It will draw three lines:

  • . A blue (base line) which will be the average of the last 6 points of temperatures.
  • . An orange offset of 0.2°C or 0.4°F.
  • . A red offset of 0.3°C or 0.6°F.

The top line is used (red line) to identify high and stable 3 consecutive points.

  • . T ° analyzable

If a point is not interpretable (Ex: fever due to angina), select "No" at "T ° analyzable" which will eliminate the point of the calculation of the "Base line".

  • . Base line

Usually the "Base line" is calculated on 6 points. But in case of long cycle, after a birth or after the pill, analysis of the "Base line" should be on 21 points. 

Additional sign: the cervix

Purpose: To determine the start of the fertility phase, the sign of the mucus is sufficient for most women. But sometimes this is not enough and you may need to observe the cervix.


We do the observation in evening after hand washing and urinating.

Standing with one foot on a chair, we introduce the index and middle fingers into the vagina, directed upwards and backwards.

After selecting the date, we note on SymptoThermal Method:

  • Height: low - medium - high
  • . The orifice of the cervix: closed - open
  • . The presence of mucus: no mucus - mucus
  • . Hardness: hard (like the end of the nose) - soft (like the ear lobe)

Learning to observe the signs of the cervix requires at the beginning the help of a monitor.

Cycle start - Peak day - Union - Comment

Cycle start

The cycle start is the first day of the menstriesmenstruation. Note on SymptoThermal Method the first day will display the days of cycle and will allow you to navigate between cycles.

Peak day

This is the last day of wetness and observation of egg white mucus followed the next day by a big change in the feel and appearance associated with an offset temperature offset.

We note on SymptoThermal Method the following evening after selecting the date of the previous day.


It notes on SymptoThermal Method when you have a union in the first part of the cycle.

After the offset temperature offset, the first union is noted on SymptoThermal Method but it is not necessary to note further unions as it does not change the interpretation.


Free text field to record any useful information to assist in the interpretation of the cycle. Examples:

  • . 'Abdominal pain'
  • . '+ 2 hrsH' if temperature taken 2 hours after the usual time
  • . 'Angina' explaining a peak of temperature 


Fertility phase:

Begins with the feeling of humidity or mucus.

Finishing the third day in the morning with an high and stable temperature of 0.3°C or 0.6°F.


Rule 1: During menstruationthe bleedings, if it is a short cycle, the mucus could be present but it will be unseen due to bleedingsmenstruation. Therefore we will not know when the fertility phase begins.

. Note 'Unknown' or '?'.

Rule 2: After menstruationthe bleedings and before the appearance of the sign of the mucus, the couple is infertile in the evening.

. Note 'Infertile the evening' or 'Ie'.

The day after an union, the couple will not know if the woman is fertile because the mucus can be masked by the residual sperm from the previous day.

. Note 'Unknown' or '?' the day after a union.

Rule 3: After an episode of mucus or bleeding (not followed by a offset temperature, so before ovulation), the couple becomes infertile after the 4th day in the evening without mucus or sensation.

. Note 'Fertile' or 'F' in the presence of mucus.

. Note 'Unknown' or '?' in the presence of bleeding.

. Note 'Unknown' or '?' the next 3 days after the presence of mucus or bleeding.

Rule 4: as soon as there is mucus or a sensation of humidity, the couple is fertile.

. Note 'Fertile' or 'F'.

Rule 5: After the offset temperature, the couple becomes infertile the third day in the morning after the temperature is high and stable with an offset of 0.3°C or 0.6°F.

. Note 'Infertile the day' or 'Id' from the third day in the morning.

Rule 6 : If it misses a data for analysis :

. 'The analysis isn't possible' and the we note: '??'.

. The 3 days after will be marked 'Unknown': '?'.

If you wish to avoid pregnancy:

You can have unions only when you are 'Infertile the evening' (first cycle period) or 'Infertile the day' (second cycle period).

If you wish to fall pregnant:

You need to have unions around the peak day.

Automatic analysis

The application 'SymptoThermal Method' provides an automatic analysis. Its quality depends on the quality of your observations.

For the application to perform the analysis, you have to specify the 'First day' of the cycle, enter data into 'Observation', 'Sensation' and 'Temperature' whose 'Last low point' the day of offset temperature.

If it misses a data for analysis, the automatic analysis isn't possible and the application note: '??'. The 3 days after will be marked undefined: '?'.

Special cases

We recommend getting help from a monitor in case of special case.

Inadequate offset temperature

Some women have a different temperature of only 0.2°C or 0.4°F.

In this case, the orange line is used to determine the offset and the couple is infertile from the 4th day in the morning instead of the 3rd day in the morning.

Long cycle

When there are 30 days or more between the first day of the cycle and the offset temperature, the 'base line' must be calculated on 21 points instead of 6.


For the first cycle, the 'basal line' must be calculated on 21 points instead of 6.

You must use an offset of 0.3°C or 0.6°F (red line) for interpretation.

The couple is infertile from the 5th day in the morning.

Post pill

For the first 3 cycles after stopping the pill, the 'base line' must be calculated on 21 points instead of 6.

You must use an offset of 0.3°C or 0.6°F (red line) for interpretation.

The couple is infertile from the 5th day in the morning.


When an offset temperature is followed by a temperature high and stable for 20 days, you are pregnant.