Basal temperature chart with explanation. What is this method used for? Special cases of basal temperature chart

Regardless of the purpose for which you decide to start monitoring the work of your body’s reproductive system, you will definitely have to start building temperature curves, learn to read and analyze them.

If you build a graph correctly, then after a few months, based on the values ​​​​displayed in it, you will already be able to assess the work of your body, you will know whether you are ovulating and when the most favorable period for this is. This knowledge should help both when planning pregnancy and for preventing unwanted conception.
Decoding the basal temperature graph has its own characteristics, and in order to learn how to accurately determine the date of ovulation and the estimated time of the onset of menstruation, you will need some time, but for this you need to familiarize yourself with the general rules for constructing such graphs and analyzing them.

If you know all the nuances of measurement, then it’s time to figure out how the obtained indicators need to be analyzed. So, with a normal ovulatory cycle, in the first phase the temperature should be lower than in the second; during ovulation there is a sharp jump upward, and by the beginning of menstruation it drops again. If on the days of the expected menstruation you see that it is growing, most likely it has already arrived.

According to the rules established by WHO, the ovulation line on the graph must be drawn when, as a result of the last 3 measurements, indicators higher than the previous 6 were obtained. Thus, the middle line is drawn over the highest value of the 6, and the next 3 indicators should be 0.1 - 0.2 C above this line. At first it may seem that deciphering the basal temperature chart and determining ovulation is a rather complicated process, but usually everything becomes clear at the first glance at the chart. If you were able to draw the midline and ovulation line, then further work with the resulting curve should not cause difficulties.

Normally, the difference between the average values ​​of the first and second phases should be more than 0.4 C, and the length of the period after ovulation should be about 12-16 days, otherwise this may indicate hormonal problems. It is also desirable that after the release of the egg, the temperature throughout the entire second phase remains around 37 C and drops only at the beginning of the critical days. If these conditions are not met on your chart, then a competent interpretation of the basal temperature chart may show that you have certain problems, even if ovulation, judging by the indicators obtained, is taking place.

If you have just started taking measurements and the first cycle turned out to be anovulatory, do not worry, but it is better to continue measuring. One or two cycles a year without the release of an egg is quite normal, but if it is absent for several months in a row, then this requires a mandatory consultation with a doctor. In this case, the interpretation should be combined with other studies: hormone tests, ultrasound, manual palpation of the pelvic organs.

Charting basal temperature is one of the methods for assessing the functioning of the reproductive system, which is available to almost every woman.

Maintaining a graph and deciphering it require compliance with certain rules and subtleties, otherwise there is a high probability of obtaining distorted results.

Keeping a graph of basal temperature allows you to determine the correct functioning of the female ovaries and identify a number of problems that affect the ability to conceive a child.

Using the graph you can determine:

• egg maturation time;
• in a particular cycle or its absence;
• favorable and unfavorable days for conception;
• presence of hormonal problems;
• diseases of the pelvic organs;
• the reason for the delay of the next menstruation.

The measurement results will be informative only if the graphs were kept for at least three menstrual cycles.

Some gynecologists observe for at least six months to accurately diagnose. For correct interpretation it is necessary. Otherwise, the graph data will not be indicative.

Building a BT schedule during pregnancy

The method of maintaining basal temperature charts is becoming increasingly widespread due to its accessibility. All you need is a thermometer, a squared notebook and a pencil.

Basal temperature is measured in the anus daily, immediately after waking up. The resulting value is entered into the table and marked on the graph.

The graph shows daily measurement results during the menstrual cycle (not a month). A normal cycle is considered to last from 21 to 35 days. The beginning of the cycle is considered the first day of menstruation (and not its end, as some people think).

Each menstrual cycle should have its own basal temperature curve.

On the vertical axis of the graph the degrees are marked (1 cell = 0.1 °C), on the horizontal axis – the days of the cycle and the date corresponding to this day. The resulting temperature value is marked on the graph by the corresponding point, after which adjacent points are connected to each other. Thus, a curve of changes in basal temperature during the cycle is constructed.

Factors that may affect the reliability of the measurement should be noted next to the corresponding day of the cycle.

These include ailments, alcohol consumption, sex shortly before measurement, insomnia, stress, and moving. Unusual temperature fluctuations caused by these factors can be excluded from the curve.

Interpretation of different types of graphs using examples: high, low and normal temperature

The graph shows the dependence of basal temperature on the phases of the menstrual cycle. In the first phase, called the follicular phase, several follicles mature. This period passes under the influence of estrogen, the temperature varies between 36.4-36.8 °C.

The first phase takes about half of the cycle. At this time, out of several follicles, one remains, and the egg matures in it.

Then the follicle bursts and the egg is released from the ovary, that is, ovulation occurs.

Before ovulation, basal temperature drops to its minimum.

The second phase of the cycle begins, during which a corpus luteum appears in place of the burst follicle. Its cells synthesize a hormone, under the influence of which a jump in basal temperature occurs by 0.4-0.8 °C. This phase is called the luteal phase.

If conception does not occur during the cycle, progesterone levels drop and basal temperature decreases slightly 2-3 days before the upcoming menstruation.

Normal two-phase schedule

The basal temperature chart for a healthy woman has clearly demarcated phases of the menstrual cycle: follicular with a low basal temperature and luteal, which is distinguished by an increase in temperature. Before ovulation and the onset of menstruation, a drop in temperature occurs.

The graph is divided into phases by the ovulation line. The follicular phase is the segment of the curve from the first day of the cycle to ovulation, the luteal phase is from ovulation to the end of the cycle. The duration of the first phase of the cycle is an individual characteristic of each woman and there are no clear requirements for it. The second phase should normally last 12-16 days.

If, over several months of observation, the length of the luteal phase does not fall within this range, a consultation with a gynecologist is necessary. This may indicate a failure of the second phase.

In a healthy woman, the duration of each phase should not vary significantly in different menstrual cycles.

Normally, the difference in average temperatures between cycle phases should be 0.4 °C or more.

To determine it, you need to add up all the basal temperature values ​​in the first phase and divide by the number of days in the phase. The average value of basal temperature in the second phase of the cycle is calculated in the same way.

Then the first is subtracted from the second indicator obtained; the result obtained characterizes the difference in average temperatures. If it is below 0.4 °C, it may be a sign of the presence of hormonal imbalance in the body.

Basal temperature chart at conception

If conception occurs during the menstrual cycle, then the basal temperature in the second phase behaves somewhat differently. It is known that after ovulation, BBT normally remains above 37 °C. However, in the cycle when pregnancy occurred 7-10 days after ovulation, the temperature drops below 37 °C. The so-called implantation retraction is observed.

Estrogen deficiency

In the case of estrogen deficiency, the graph does not divide the cycle into clear phases, since low estrogen levels provoke an increase in temperature in the follicular phase of the cycle. The curve is chaotic, it is impossible to determine the date of ovulation.

Conception in this case is unlikely; you should consult a gynecologist. If estrogen deficiency is confirmed after additional examinations, the patient will be prescribed treatment with hormonal drugs.

Anovulatory cycle

In the absence of ovulation, the graph looks like a monotonous curve without division into phases. In the second phase of the menstrual cycle, the basal temperature remains low and does not exceed 37 °C. In such a cycle, the formation that synthesizes progesterone does not occur, so the basal temperature does not increase in the second half of the cycle.

A couple of anovulatory cycles per year is normal, but if the situation repeats for several months in a row, you should consult a doctor. Pregnancy without ovulation is impossible, so it is necessary to find the root of the problem together with a gynecologist.

The difference in average temperatures between the phases of the cycle is 0.2-0.3 °C. If such graphs are built over several cycles in a row, this may be a sign of infertility due to hormonal imbalances.

If the corpus luteum does not function effectively enough and does not produce the required amount of progesterone, the temperature in the second phase of the cycle rises slightly. In this case, the duration of the second phase is reduced to 10 days and there is no drop in basal temperature before the onset of menstruation.

If the corpus luteum is insufficient, fertilization of the egg is possible, but there is a high risk of its rejection in the same cycle.

To confirm the diagnosis, a woman needs to undergo a blood test for progesterone.

Diagnosed corpus luteum deficiency is corrected by taking artificial progesterone analogs (“” or “”) in the luteal phase of the cycle.

Prolactin is a hormone responsible for pregnancy and breastfeeding. Normally, in a non-pregnant woman it is absent or its level is extremely low.

If for certain reasons it increases, the basal temperature chart becomes identical. In this case, there may be a lack of menstruation.

Inflammation of the appendages

The presence of an inflammatory process can be suspected by a jump in temperature in the first segment of the graph. A high basal temperature is observed in the first phase of the cycle.

It rises sharply to 37 °C and after a few days decreases sharply. Such a jump can be mistaken for an ovulatory rise in temperature, so with this type of graph it can be difficult to determine the onset of ovulation.

Endometritis

Normally, with the arrival of critical days, the basal temperature should decrease. With endometritis (inflammation of the uterine mucosa), there is a drop in temperature before the onset of menstruation and a rise to 37 °C in the first phase of the menstrual cycle.

Keeping basal temperature charts is an accessible and safe method for determining favorable and unfavorable days for conception. But due to its high sensitivity, it requires a responsible and competent approach, otherwise maintaining a schedule loses its practical meaning.

Even if the graph is constructed correctly, you need to remember that the final diagnosis is never made solely on the basis of analysis of the curve data. Any diagnosis must be confirmed by tests and additional studies.

If you care about your health and decide to learn more about the processes occurring in your body, then an easy way to do this is to plot your basal temperature.

Let's say you went through this painstaking work, and as a result you received a graph with a jumping line, that is, a curve located in some way. Congratulations on your result! What's next? You look at these dots and lines and there are probably no considerations. The thing is that the average woman does not have the data to decipher the basal temperature chart. Of course, it’s best to entrust this matter to a doctor, but it’s also a good idea to figure out what’s what yourself. I think this article will help you understand what you see on the graph means.

But we will not consider the main five types of graphs, you can read about this in many other articles, but let’s talk about what hidden problems in your body the type of temperature curve can tell. After all, if you build a graph according to all the rules, strictly following the existing instructions, then the result obtained can indicate not only the onset or absence of the ovulation process, but can also reveal some diseases.

Notation on a regular chart

Below is a normal two-phase graph, which clearly shows the pre-ovulatory drop in the temperature curve on day 12 (the temperature drops quite noticeably two days before ovulation), as well as the premenstrual drop that occurs from the 26th day of the cycle.

Let's try to “read” this graph. What do the lines on it mean? The covering line on the temperature curve graph is drawn on top of 6 temperature indicators in the initial phase of the cycle, which occur before ovulation.

And the initial 5 days of the cycle and the days when the temperature could be distorted by various negative influences are not taken into account. No significant conclusions are drawn along this line; it is needed rather as a guide.

The second line on the basal temperature chart is the ovulation line.

There are clearly defined WHO rules by which the completed process of ovulation is determined. They are described below. It is better to read them by looking at the temperature curve graph, otherwise it is difficult to understand.

Three temperature readings in a row should be located above the level of the line drawn on top of the 6 previous temperature readings.

The most effective time, according to generally accepted opinion, is the day of ovulation and the two days preceding it.

By the way, did you know that every woman can experience a couple of unfulfilled ovulation cycles a year - this is natural and you don’t have to consult a doctor, however, if ovulation does not occur often, then this requires a mandatory visit to a gynecologist. After all, the chances of getting pregnant are zero if ovulation does not occur during your menstrual cycle.

When temperature charts indicate illness

Suspect inflammation of the appendages possible if increased temperature is evident in the first phase of the menstrual cycle. With this diagnosis, the temperature will increase only for a couple of days in the first phase and reach 37 degrees, and then drop again. On such a graph, it is almost impossible to establish that ovulation has occurred, because it is hidden by the ovulatory surge.

Based on the basal temperature chart, you can determine the presence endometritis.

In the usual case, the temperature in the initial phase should drop sometimes during menstrual bleeding. And with endometritis, the temperature at the end of the cycle decreases even before the onset of menstruation and increases again, reaching 37 degrees with the onset of menstruation.

What explains the low temperature in the final phase according to the temperature curve graph.

In the final phase of cycle b. i.e. normally it should differ significantly (within 0.4 degrees) from the initial phase, and remain at 37 degrees or more, provided that you use the rectal method of measuring temperature. And when the temperature fluctuation is less than 0.4 degrees and the calculated average temperature of the final phase does not reach 36.8 degrees, then this indicates undetected violations and in this situation, additional examination will not hurt.

Based on the basal temperature chart, the lack of corpus luteum.

In the final period of the cycle, the woman’s body produces the hormone progesterone, or it is also called the corpus luteum hormone. Such a hormone affects the temperature increase at the final stage of the cycle and does not allow the onset of menstruation. If this hormone is present in small doses, the temperature rises very slowly and pregnancy may be in danger.

When there is a lack of corpus luteum, the temperature rises immediately before menstruation, and “premenstrual” retraction does not occur. This is also considered an indicator of hormonal deficiency. To make a diagnosis, you need to do a blood test for progesterone levels in the second part of the cycle.

If its quantity is not enough, then the gynecologist often prescribes a progesterone substitute: utrozhestan or duphaston. Such drugs are used strictly after the ovulation process has occurred. If you are pregnant, taking these medications continues for up to 10-12 weeks. Because if you abruptly stop taking the drug and thereby stop the flow of progesterone into the woman’s body, then in the second phase, when pregnancy begins, there may be a threat of termination of pregnancy. Here is a graph formed when there is a lack of corpus luteum.

A graph that shows that the basal temperature remains high for more than 14 days indicates pregnancy or the formation of a cyst (corpus luteum of the ovary).

There is still, I hope, a deviation unfamiliar to you - hyperprolactinemia.

The reason for this condition is an increase in prolactin, which is responsible for the normal course of pregnancy and good lactation. The graph of the temperature curve in this case coincides with the graph of a pregnant woman. Menstruation, just like during pregnancy, may not occur. Below is a sample graph of basal temperature in a state of hyperprolactinemia.

Paying close attention to your health will help you identify health problems in your body in a timely manner. And this, in turn, will help you see a doctor in time and achieve recovery with little effort.

Basal body temperature (BBT or BBT) is the temperature that is established after a person has substantially rested. Its measurement allows you to obtain comprehensive information about the functions of a woman’s body - to determine ovulation, the level of sex hormones and their balance, as well as possible pregnancy and the likelihood of its pathological course. How to correctly determine BT and build a graph? And is it possible to identify normality and pathology in this way?

The basal temperature is the temperature the body has at rest. A prerequisite for correct measurement is a previous rest of three to six hours. Therefore, it is optimal to determine readings after sleep. Despite the simplicity of the study, this method fully reflects the hormonal fluctuations in a woman’s body, the function of the ovaries and the condition of the organs of the reproductive system. Therefore, constructing a curve based on the measured basal temperature is the first thing that needs to be done at home in order to determine ovulation and know how and when best to plan a pregnancy.

The essence of the method

Back in 1950, the role of sex hormones in the formation of a woman’s body temperature was experimentally proven. The concentration of the estrogen and progestogen components of the hormonal background changes throughout the cycle. The processes of ovulation and the formation of the endometrium (inner layer of the uterus) in the second phase depend on the level of sex hormones. A sufficient amount of them is important for the normal course of pregnancy, and a deficiency causes threat symptoms and detachment of the ovum.

Normally, an increase in the level of estrogen hormones leads to a decrease in metabolic processes and, accordingly, the temperature of the pelvic organs, which is observed in the first phase of the cycle. Progesterone stimulates the thermoregulation center, leading to its slight increase in the second phase. On the curve being built, this is clearly expressed as an increase of half a degree or more.

The main disadvantage of the method is its relativity - a normal schedule may be accompanied by a decrease in the level of estrogen and progesterone in absolute numbers. But the simplicity and accessibility of implementation at home, and the information content make it possible to widely use this method when planning pregnancy and for the initial detection of functional disorders in a woman.

What you can find out

• whether ovulation occurs (the release and maturation of an egg) and on what days;
• identify two-phase cycle or any deviations;
• approximate level of estrogen and progestogen fractions of hormones;
• infertility factor;
• when will you have your period;
• whether conception occurred;
• identify “safe” days for intimate relationships;
• suspect inflammatory processes in the uterus.

The basal temperature chart is visual material that can be provided to the doctor. Already at the first appointment, its decoding can be of great help in ordering additional examination for the woman.

When is it useful to use the method

A schedule can be created for everyone, for example, for contraception. BT will increase on the day of ovulation; at this time, additional measures should be taken to protect against pregnancy. A change in BT is prescribed for diagnostic purposes:

• for problems with conception;
• in case of doubtful pregnancy;
• in order to increase the likelihood of conception.

Only a professional can correctly analyze the result. An obstetrician-gynecologist thoroughly knows how basal temperature changes during ovulation and pregnancy.

How to make your research accurate

It is important to know how to correctly measure and record the result of basal temperature, especially if this is necessary to determine ovulation. Essentially, this is a determination of the metabolic rate and heat transfer in the pelvic organs. To obtain the most accurate data, it is necessary to conduct research in the rectum. This way, even the slightest fluctuations can be recorded, which can affect the result and interpretation of the data. It is also recommended to follow the rules:

• rest for at least 3 hours right before the measurement;
• refrain from intimate contacts before measurement;
• avoid stress;
• limit the consumption of spicy and highly salted foods;
• monitor normal bowel function;
• use one thermometer (electronic or mercury).

How to do it correctly

Measuring BT can be started at any convenient time - before, during or after menstruation. Simple recommendations will help you get the most accurate result.

• Where to measure. To solve gynecological problems, it is necessary to measure the temperature in the rectum. Other areas will not be suitable, the result will be biased.
• On what days? It is necessary to determine the temperature on all days of the menstrual cycle. A special graph is used to record the results. There is no need to skip measurements on critical days.
• What time. It is optimal to conduct the study in the morning. A prerequisite is three hours of rest. It is not recommended to even shake the thermometer before measuring, much less get up to go to the toilet or just get out of bed. If a woman works at night, the measurement should be taken after three hours of sleep during the day or even in the evening. It is advisable to make notes about such shifts in the table chart. It is necessary to take measurements at the same time every day with intervals of no more than one and a half to two hours.
• How to prepare. If a girl begins to measure rectal temperature, she should make sure that the thermometer lies next to her bed every day, and she can conduct the examination without getting out of bed.
• Which weeks to measure by? To obtain reliable information, it is necessary to conduct the study according to plan for at least 10-12 weeks in a row (two to three months). Even normally, a woman does not ovulate every month, especially after 35 years.
• Which thermometer is better? A mercury thermometer is considered more accurate. It must first be brought down to the minimum readings in the evening, so as not to perform additional actions in the morning. You should not put a mercury thermometer under your pillow - it can easily break. The use of an electronic thermometer is allowed. It is easier and safer to handle, but may be somewhat inferior in accuracy.
• How to record the result. It is better to write down the testimony immediately, without relying on your memory. Daily differences will be tenths of a degree, so they can be easily confused. It is advisable to record additional factors that could influence the result. For example, drinking alcohol, moving, illness, sleep disturbance.

Ideally basal temperature readings

Normally, the curve looks like “gull wings in flight.” This is a figurative expression that doctors often use in their practice. In order to be able to clearly track changes on the graph, it is necessary to adhere to a number of conditions:

• start from the first day of bleeding;
• enter parameters into the chart daily;
• Draw a line as you fill;
• find out the day of ovulation;
• additionally note the nature of the discharge;
• You can use developed programs for data entry.

Filling out the chart accurately will help make it as informative as possible. According to reviews from women who have long been practicing determining rectal temperature, it is simple and does not require special medical knowledge. You can compare the obtained indicators with the norm using the following table.

Table - Important values ​​in the BT chart and normal options

If there is a balance of sex hormones, the readings of the second phase should be 0.4-0.6 °C greater than the first. Only a specialist can most accurately and reliably compare the information presented in the table and obtained during measurements.

Possible deviations

It is difficult to conduct an in-depth analysis of the basal temperature chart on your own; if ovulation is disrupted, it may have a non-standard appearance. Therefore, it is better to contact a gynecologist for a detailed explanation, especially if there are any problems (with pregnancy, conception).

Doctors and women have to deal with the following deviations.

• During critical days, the readings are higher. It could be double ovulation, but this is a rare occurrence. Most often, an increase in rectal temperature above 37 °C indicates the presence of a sluggish inflammatory process in the uterine cavity.
• Increased BT values ​​for the first 14 days. If the reading is above 36.6 °C, then the estrogen level is not enough to lower it. As a result, the egg does not mature.
• After ovulation, the rise is smooth, not sharp. This indicates the inferiority of the egg. She either does not have time to ripen, or she does not have enough hormone emissions for full ovulation.
• The second phase of the cycle is short. Normally, after ovulation, at least 12-14 days should pass before the onset of menstruation. A shortening of the period indicates insufficient hormonal support. Even if conception occurs at this time (the basal temperature chart during pregnancy will also have high numbers), the fertilized egg will not have enough hormonal support and will die. Duphaston (artificial gestagen) prescribed in a timely manner will help maintain pregnancy in such situations. Reviews from women whose “miracle” appeared thanks to this drug prove its effectiveness.
• A sharp drop, and then a slight rise in the second phase. Such “pits” are direct evidence of the sudden death of the egg.
• Small difference in the average readings of the first and second phases. If a low basal temperature is observed until the end of the cycle after ovulation, most likely the reason lies in the inadequate production of progesterone.
• Temperature high/low throughout the cycle. If the normal difference between the average values ​​remains (0.4-0.6), this may be an individual manifestation of increased or decreased temperature of the whole body.
• The temperature peak shifts to the right or left. This can be observed with early (for example, on days 5-7) or late ovulation (on days 21-23); the usefulness of such ovulation can be judged by a jump in temperature. In this case, the second phase of the cycle will be shortened or lengthened accordingly.
• No climbs at all. The absence of peaks in basal temperature indicates that the cycles are without ovulation (anovulatory).
• While taking estrogen-progestogen tablets. There is no point in making a schedule when using hormonal contraceptives, since they create an anovulatory state in the body.

What changes are recorded during normal and pathological pregnancy?

When constructing curves, one is always interested in the question of how and when one can determine whether pregnancy has occurred based on basal temperature. After all, when tracking ovulation, most do this in order to increase the likelihood of conception.

The way basal temperature changes is important only in the early stages of pregnancy - in the 1st trimester. In the 2nd and 3rd trimesters, there are other diagnostic signs and more reliable studies. The following options are possible.

• With successful gestation. Normally, after conception, the basal temperature rises and remains elevated throughout pregnancy, which is especially clearly noticeable in the early stages of pregnancy, when women even notice a rise in the temperature of the whole body. Even before the delay, it will be possible to find out that conception has occurred. Moreover, it does not matter at all how many fruits a woman bears: one, twins or more. After all, the curve shows relative, not absolute values. If the curve has already decreased, but there are no periods, pregnancy is unlikely - this is a cycle failure.
• With an ectopic pregnancy. The graph is influenced by the location of the ovum, and how intensively the corpus luteum produces progesterone. Therefore, if the embryo develops without deviations, BT during an ectopic pregnancy in the early stages will be the same as normal.
• During a frozen pregnancy. Just before the embryo stops developing further, a low basal temperature suddenly appears, which no longer rises during a given pregnancy.
• If there is a threat of miscarriage. Often the cause of the threat is a lack of progesterone. In this case, the basal temperature during pregnancy will fall or tend to decrease. If the reason is different, then there may be no changes in the graph. If bloody discharge appears against the background of a high basal temperature, you should immediately consult a doctor.
• Stimulation of ovulation in case of infertility. In this case, the artificial hormonal background will create an ideal basal temperature curve before and after ovulation, including later in pregnancy if fertilization has occurred.

You shouldn’t talk about pregnancy prognosis based on basal temperature alone. The process of gestation may be influenced by other circumstances that are not always reflected on the graph (pathology of embryo development, infection).

Thus, measuring rectal temperature is an accessible and simple method for monitoring the functions of the female body. This functional diagnostic test often helps to clarify infertility problems and various endocrine disorders. During pregnancy, basal temperature normally increases before menstruation, and if fertilization has not occurred, it decreases. If all recommendations are followed, this method is more reliable than any pregnancy test. It is informative and advisable to measure temperature only up to the 2nd trimester.

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Measuring basal temperature has become a truly popular means of pregnancy planning.

Why measure basal temperature
Basal or rectal temperature (BT)- This is the body temperature at rest after at least 3-6 hours of sleep, the temperature is measured in the mouth, rectum or vagina. The temperature measured at this moment is practically not affected by environmental factors. Experience shows that many women perceive the doctor’s demands to measure basal temperature as a formality and basal temperature does not solve anything, but this is far from the case.

The method of measuring basal body temperature was developed in 1953 by the English professor Marshall and refers to research techniques that are based on the biological effect of sex hormones, namely on the hyperthermic (increase in temperature) action of progesterone on the thermoregulation center. Measuring basal body temperature is one of the main tests for the functional diagnosis of ovarian function. Based on the results of measuring BT, a graph is constructed; an analysis of basal temperature graphs is given below.

Measuring basal temperature and charting is recommended in gynecology in the following cases:

• If you have been trying to get pregnant for a year without success
• If you suspect yourself or your partner is infertile
• If your gynecologist suspects you have hormonal disorders

In addition to the above cases, when charting basal body temperature is recommended by a gynecologist, You can measure your basal body temperature if:

• Do you want to increase your chances of pregnancy?
• You are experimenting with methods of planning the gender of your child
• You want to observe your body and understand the processes taking place in it (this can help you communicate with specialists)

Experience shows that many women perceive the doctor’s demands to measure basal temperature as a formality and it does not solve anything.

In fact, By measuring your basal body temperature, you and your doctor can find out:

• Does the egg mature and when does this happen (accordingly, highlight “dangerous” days for the purpose of protection or, conversely, the possibility of getting pregnant);
• Did ovulation occur after the egg matured?
• Determine the quality of your endocrine system
• Suspect gynecological problems, such as endometritis
• When to expect your next menstruation
• Whether pregnancy occurred due to delay or unusual menstruation;
• Assess how correctly the ovaries secrete hormones according to the phases of the menstrual cycle;

A graph of basal temperature, drawn up according to all measurement rules, can show not only the presence of ovulation in a cycle or its absence, but also indicate diseases of the reproductive and endocrine systems. You must measure your basal temperature for at least 3 cycles so that the information accumulated during this time allows you to make accurate predictions about the expected date of ovulation and the most favorable time of conception, as well as conclusions about hormonal disorders. Only a gynecologist can give an accurate assessment of your basal temperature chart. Drawing up a basal temperature chart can help a gynecologist determine deviations in the cycle and suggest the absence of ovulation, but at the same time, a gynecologist’s diagnosis based solely on the basal temperature chart without additional tests and examinations most often indicates medical unprofessionalism.

It is necessary to measure the basal temperature, and not the body temperature at the armpit. A general increase in temperature as a result of illness, overheating, physical activity, eating, stress, naturally affects the basal temperature readings and makes them unreliable.

Thermometer for measuring basal temperature.

You will need a regular medical thermometer: mercury or electronic. The basal temperature is measured with a mercury thermometer for five minutes, but the electronic thermometer must be removed after the signal about the end of the measurement. After it squeaks, the temperature will continue to rise for some time, since the thermometer records the moment when the temperature rises above very slowly (and don’t listen to the nonsense about the thermometer not being in good contact with the muscles of the anus). The thermometer must be prepared in advance, in the evening, by placing it next to the bed. Do not place mercury thermometers under your pillow!

Rules for measuring basal temperature.
1. You should measure your basal temperature every day if possible, including on your period.

2. You can measure in the mouth, vagina or rectum. The main thing is that the measurement location does not change throughout the entire cycle. Measuring armpit temperature does not provide accurate results. With the oral method of measuring basal temperature, you place the thermometer under your tongue and measure for 5 minutes with your mouth closed.
When using the vaginal or rectal method of measurement, insert the narrow part of the thermometer into the anus or vagina, the measurement duration is 3 minutes. Measuring temperature in the rectum is the most common.

3. Measure your basal temperature in the morning, immediately after waking up and before getting out of bed.

4. It is necessary to measure basal temperature at the same time (a difference of half an hour to an hour (maximum one and a half hours) is acceptable). If you decide to sleep longer on the weekend, make a note about it in your schedule. Keep in mind that every extra hour of sleep raises your basal temperature by about 0.1 degrees.

5. Continuous sleep before measuring basal temperature in the morning should last at least three hours. Therefore, if you take your temperature at 8 am, but got up at 7 am to go, for example, to the toilet, it is better to measure your BT before that, otherwise, at your usual 8 o’clock it will no longer be informative.

6. You can use either a digital or a mercury thermometer to measure. It is important not to change the thermometer during one cycle.
If you use a mercury thermometer, shake it off before going to sleep. The effort you use to shake off the thermometer immediately before measuring your basal temperature can affect your temperature.

7. Basal temperature is measured while lying still. Do not make unnecessary movements, do not turn, activity should be minimal. Do not under any circumstances get up to take a thermometer! Therefore, it is better to prepare it in the evening and place it near the bed so that you can reach the thermometer with your hand. Some experts advise taking the measurement without even opening your eyes, since daylight can increase the release of certain hormones.

8. Readings from the thermometer are taken immediately after it is removed.

9. After measurement, it is best to immediately write down your basal temperature. Otherwise you will forget or get confused. The basal temperature is approximately the same every day, differing by tenths of degrees. Relying on your memory, you can get confused in the readings. If the thermometer readings are between two numbers, record the lower reading.

10. The schedule must indicate the reasons that could lead to an increase in basal temperature (acute respiratory infections, inflammatory diseases, etc.).

11. Business trips, travel and flights, sexual intercourse the night before or in the morning can significantly affect basal temperature.

12. In case of illnesses accompanied by elevated body temperature, your basal temperature will be uninformative and you can stop taking measurements for the duration of your illness.

13. Various medications, such as sleeping pills, sedatives and hormonal drugs, can affect basal temperature.
Measuring basal temperature and simultaneous use of oral (hormonal) contraceptives does not make any sense. Basal temperature depends on the concentration of hormones in the tablets.

14. After drinking a large amount of alcohol, the basal temperature will be uninformative.

15. When working at night, basal temperature is measured during the day after at least 3-4 hours of sleep.

The basal body temperature (BT) recording table should contain the following lines:

Day of the month
Cycle day
BT
Notes: Heavy or moderate discharge, abnormalities that can affect BT: general illness, including fever, diarrhea, intercourse in the evening (and even more so in the morning), drinking alcohol the day before, measuring BT at unusual times, going to bed late (for example , went to bed at 3 o’clock, and measured at 6), taking sleeping pills, stress, etc.

All factors that could in one way or another affect the change in basal temperature are entered in the “Notes” column.

This form of recording greatly helps both the woman and her doctor to understand the possible causes of infertility, cycle disorders, etc.

Rationale for the basal body temperature method

Basal body temperature changes during the cycle under the influence of hormones.

During the maturation of the egg against the background of a high level of estrogen (the first phase of the menstrual cycle, hypothermic, “low”), the basal temperature is low; on the eve of ovulation it drops to its minimum, and then rises again, reaching a maximum. At this hour, ovulation occurs. After ovulation, a phase of high temperature begins (the second phase of the menstrual cycle, hyperthermic, “high”), which is caused by low levels of estrogen and high levels of progesterone. Pregnancy under the influence of progesterone also occurs entirely in a high temperature phase. The difference between the “low” (hypothermic) and “high” (hyperthermic) phases is 0.4-0.8 °C. Only with an accurate measurement of basal body temperature can one record the level of “low” temperature in the first half of the menstrual cycle, the transition from “low” to “high” on the day of ovulation, and the level of temperature in the second phase of the cycle.

Usually during menstruation the temperature remains at 37°C. During the period of follicle maturation (the first phase of the cycle), the temperature does not exceed 37°C. Just before ovulation it decreases (the result of the action of estrogen), and after it the basal temperature rises to 37.1 ° C and higher (the influence of progesterone). Until the next menstruation, the basal temperature remains elevated and decreases slightly by the first day of menstruation. If the basal temperature in the first phase, relative to the second, is high, then this may indicate a low amount of estrogen in the body and requires correction with medications containing female sex hormones. On the contrary, if in the second phase, relative to the first, a low basal temperature is observed, then this is an indicator of low progesterone levels and drugs are also prescribed to correct hormonal levels. This should be done only after passing the appropriate hormone tests and a doctor’s prescription.

A persistent two-phase cycle indicates ovulation, which has taken place, and the presence of a functionally active corpus luteum (the correct rhythm of the ovaries).
The absence of a rise in temperature in the second phase of the cycle (monotonic curve) or significant temperature swings, both in the first and second half of the cycle with the absence of a stable rise, indicates inoculation (lack of release of the egg from the ovaries).
Delayed rise and its short duration (hypothermic phase for 2-7, up to 10 days) is observed with a shortening of the luteal phase, insufficient rise (0.2-0.3 ° C) - with insufficient functioning of the corpus luteum.
The thermogenic effect of progesterone leads to an increase in body temperature by at least 0.33 ° C (the effect lasts until the end of the luteal, that is, the second, phase of the menstrual cycle). Progesterone levels peak 8-9 days after ovulation, which roughly corresponds to the time the fertilized egg implants into the uterine wall.

By charting your basal temperature, you can not only determine when you ovulate, but also find out what processes are occurring in your body.

Interpretation of basal temperature charts. Examples

If the basal temperature chart is constructed correctly, taking into account the measurement rules, it can reveal not only the presence or absence of ovulation, but also some diseases.

Covering line
The line is drawn over 6 temperature values ​​in the first phase of the cycle preceding ovulation.
This does not take into account the first 5 days of the cycle, as well as days on which the temperature could be affected by various negative factors (see rules for measuring temperature). This line does not allow any conclusions to be drawn from the graph and is for illustrative purposes only.

Ovulation line
In order to judge the onset of ovulation, the rules established by the World Health Organization (WHO) are used:
Three temperature values ​​in a row must be above the level of the line drawn over the previous 6 temperature values.
The difference between the center line and the three temperature values ​​must be at least 0.1 degrees on two days out of three and at least 0.2 degrees on one of those days.

If your temperature curve meets these requirements, then an ovulation line will appear on your basal temperature chart 1-2 days after ovulation.
Sometimes it is not possible to determine ovulation using the WHO method due to the fact that there are high temperatures in the first phase of the cycle. In this case, you can apply the “finger rule” to the basal temperature chart. This rule excludes temperature values ​​that differ from the previous or subsequent temperature by more than 0.2 degrees. Such temperature values ​​should not be taken into account when calculating ovulation if the overall basal temperature chart is normal.
The most optimal time for conception is the day of ovulation and 2 days before it.

Menstrual cycle length
The total length of the cycle should normally not be shorter than 21 days and should not exceed 35 days. If your cycles are shorter or longer, then you may have ovarian dysfunction, which is often the cause of infertility and requires treatment by a gynecologist.

Second phase length
The basal temperature chart is divided into the first and second phases. The division takes place where the ovulation line (vertical) is marked. Accordingly, the first phase of the cycle is the segment of the graph before ovulation, and the second phase of the cycle is after ovulation.

The length of the second phase of the cycle is normally from 12 to 16 days, most often 14 days. In contrast, the length of the first phase can vary greatly and these variations are the individual norm. At the same time, in a healthy woman in different cycles there should be no significant differences in the length of the first phase and the second phase. The total length of the cycle normally changes only due to the length of the first phase.

One of the problems identified on the graphs and confirmed by subsequent hormonal studies is the failure of the second phase. If you measure your basal temperature over several cycles, following all the measurement rules, and your second phase is shorter than 10 days, this is a reason to consult a gynecologist. Also, if you regularly have sexual intercourse during ovulation, pregnancy does not occur and the length of the second phase is at the lower limit (10 or 11 days), then this may indicate insufficiency of the second phase.

Temperature difference
Normally, the difference in average temperatures of the first and second phases should be more than 0.4 degrees. If it is lower, this may indicate hormonal problems. Get a blood test for progesterone and estrogen and consult a gynecologist.

An increase in basal temperature occurs when serum progesterone levels exceed 2.5-4.0 ng/ml (7.6-12.7 nmol/l). However, monophasic basal temperature has been identified in a number of patients with normal progesterone levels in the second phase of the cycle. In addition, monophasic basal temperature is observed in approximately 20% of ovulatory cycles. A simple statement of biphasic basal temperature does not prove the normal function of the corpus luteum. Basal temperature also cannot be used to determine the time of ovulation, since even during luteinization of an unovulated follicle, a two-phase basal temperature is observed. Nevertheless, the duration of the luteal phase in accordance with basal temperature data and the low rate of rise in basal temperature after ovulation are accepted by many authors as criteria for diagnosing luteinization syndrome of a non-ovulating follicle.

Classic gynecological manuals describe five main types of temperature curves.

Normal two-phase cycle according to the basal temperature chart
Such graphs indicate an increase in temperature in the second phase of the cycle by at least 0.4 C; a noticeable “preovulatory” and “premenstrual” drop in temperature. The duration of the temperature increase after ovulation is 12-14 days. This curve is typical for a normal two-phase menstrual cycle.

The example graph shows a pre-ovulatory drop on the 12th day of the cycle (the temperature drops significantly two days before ovulation), as well as a premenstrual drop starting from the 26th day of the cycle.

There is a slight rise in temperature in the second phase. The temperature difference in the first and second phases is no more than 0.2-0.3 C. Such a curve may indicate estrogen-progesterone deficiency. See examples of graphs below.

If such graphs are repeated from cycle to cycle, then this may indicate hormonal imbalances that cause infertility.
Basal temperature begins to rise only shortly before menstruation, and there is no “premenstrual” drop in temperature. The second phase of the cycle can last less than 10 days. This curve is typical for a two-phase menstrual cycle with insufficiency of the second phase. See examples of graphs below.

Pregnancy in such a cycle is possible, but it is under threat from the very beginning. At this moment, the woman cannot yet know about the pregnancy; even gynecologists would find it difficult to make a diagnosis at such an early stage. With such a schedule, we may not be talking about infertility, but about miscarriage. Be sure to contact your gynecologist if this schedule repeats for you for 3 cycles.

In a cycle without ovulation, the corpus luteum, which produces the hormone progesterone and affects the increase in basal body temperature, does not form. In this case, the basal temperature chart does not show a rise in temperature and ovulation is not detected. If there is no ovulation line on the graph, then we are talking about an anovulatory cycle.

Each woman may have several anovulatory cycles per year - this is normal and does not require medical intervention, but if this situation repeats from cycle to cycle, then be sure to consult a gynecologist. Without ovulation, pregnancy is impossible!
A monotonous curve occurs when there is no pronounced rise throughout the entire cycle. This schedule is observed during an anovulatory (no ovulation) cycle. See examples of graphs below.

On average, a woman has one anovulatory cycle per year and there is no reason to worry in this case. But anovulatory patterns that are repeated from cycle to cycle are a very serious reason to consult a gynecologist. Without ovulation, a woman cannot become pregnant and we are talking about female infertility.

Estrogen deficiency
Chaotic temperature curve. The graph shows large temperature ranges; it does not fit into any of the types described above. This type of curve can be observed both with severe estrogen deficiency and depend on random factors. Examples of graphs are below.
A competent gynecologist will definitely require hormone tests and conduct an ultrasound examination before prescribing medications.

High basal temperature in the first phase

The basal temperature chart is divided into the first and second phases. The division takes place where the ovulation line (vertical line) is marked. Accordingly, the first phase of the cycle is the segment of the graph before ovulation, and the second phase of the cycle is after ovulation.

Estrogen deficiency
In the first phase of the cycle, the hormone estrogen dominates in the female body. Under the influence of this hormone, the basal temperature before ovulation averages between 36.2 and 36.5 degrees. If the temperature in the first phase rises and remains above this level, then estrogen deficiency can be assumed. In this case, the average temperature of the first phase rises to 36.5 - 36.8 degrees and is maintained at this level. To increase estrogen levels, gynecologists-endocrinologists will prescribe hormonal medications.

Estrogen deficiency also leads to elevated temperature in the second phase of the cycle (above 37.1 degrees), while the rise in temperature is slower and takes more than 3 days.

Using the example graph, the temperature in the first phase is above 37.0 degrees, in the second phase it rises to 37.5, the rise in temperature by 0.2 degrees on days 17 and 18 of the cycle is insignificant. Fertilization in a cycle with such a schedule is very problematic.

Inflammation of the appendages
Another reason for the increase in temperature in the first phase may be inflammation of the appendages. In this case, the temperature rises only for a few days in the first phase to 37 degrees, and then drops again. In such graphs, calculating ovulation is difficult, since such a rise “masks” the ovulatory rise.

In the example graph, the temperature in the first phase of the cycle is kept at 37.0 degrees, the increase occurs sharply and also decreases sharply. A rise in temperature on the 6th day of the cycle can be mistakenly taken for an ovulatory rise, but in fact it most likely indicates inflammation. That's why it's so important to measure your temperature throughout your cycle to rule out a scenario where your temperature rises due to inflammation, then drops again, and then rises due to ovulation.

Endometritis
Normally, the temperature in the first phase should decrease during menstrual bleeding. If your temperature at the end of the cycle drops before the start of menstruation and rises again to 37.0 degrees with the beginning of menstruation (less often on the 2-3rd day of the cycle), then this may indicate the presence of endometritis.

Low temperature in the second phase of the menstrual cycle

In the second phase of the cycle, the basal temperature should differ significantly (by about 0.4 degrees) from the first phase and be at 37.0 degrees or higher if you measure the temperature rectally. If the temperature difference is less than 0.4 degrees and the average temperature of the second phase does not reach 36.8 degrees, then this may indicate problems.

Corpus luteum deficiency
In the second phase of the cycle, the female body begins to produce the hormone progesterone or the hormone of the corpus luteum. This hormone is responsible for raising the temperature in the second phase of the cycle and preventing the onset of menstruation. If this hormone is not enough, the temperature rises slowly and the resulting pregnancy may be in jeopardy.

The temperature with corpus luteum deficiency rises shortly before menstruation, and there is no “premenstrual” drop. This may indicate hormonal deficiency. The diagnosis is made based on a blood test for progesterone in the second phase of the cycle. If its values ​​are reduced, then the gynecologist usually prescribes a progesterone substitute: utrozhestan or duphaston. These drugs are taken strictly after ovulation. If pregnancy occurs, use continues until 10-12 weeks. Abrupt withdrawal of progesterone in the second phase during pregnancy can lead to the threat of termination of pregnancy.

Particular attention should be paid to charts with a short second phase. If the second phase is shorter than 10 days, then one can also judge that the second phase is insufficient.
Situations when the basal temperature remains elevated for more than 14 days occur during pregnancy, the formation of an ovarian corpus luteum cyst, as well as during an acute inflammatory process of the pelvic organs.

Estrogen-progesterone deficiency
If, in combination with low temperature in the second phase, your chart shows a slight rise in temperature (0.2-0.3 C) after ovulation, then such a curve may indicate not only a lack of progesterone, but also a lack of the hormone estrogen.

Hyperprolactinemia
Due to an increase in the level of the pituitary hormone, prolactin, which is responsible for maintaining pregnancy and lactation, the basal temperature graph in this case may resemble the graph of a pregnant woman. Menstruation, just like during pregnancy, may be absent. An example of a basal temperature chart for hyperprolactinemia

Basal temperature chart for ovulation stimulation
When stimulating ovulation, in particular with clomiphene (clostilbegit) with the use of duphaston in the second phase of breastfeeding, the basal temperature graph, as a rule, becomes “normal” - two-phase, with a pronounced phase transition, with a fairly high temperature in the second phase, with characteristic “steps” (temperature rises 2 times) and slight depression. If the temperature graph during stimulation, on the contrary, is disrupted and deviates from normal, this may indicate an incorrect selection of the dose of drugs or an inappropriate stimulation scenario (other medications may be needed). An increase in temperature in the first phase upon stimulation with clomiphene also occurs with individual sensitivity to the drug.

Special cases of basal temperature chart
Low or high temperature in both phases, provided that the temperature difference is at least 0.4 degrees, is not a pathology. This is an individual feature of the body. The measurement method can also affect the temperature values. Typically, with an oral measurement, the basal temperature is 0.2 degrees lower than with a rectal or vaginal measurement.

When to contact a gynecologist?

If you strictly follow the rules for measuring temperature and observe the problems described on your basal temperature chart in at least 2 cycles in a row, consult a doctor for additional examinations. Beware of your gynecologist making diagnoses based solely on charts. What you need to pay attention to:

• ◦anovulatory schedules
• regular cycle delays when pregnancy does not occur
• late ovulation and failure to become pregnant for several cycles
• controversial charts with unclear ovulation
• graphs with high temperature throughout the cycle
• graphs with low temperature throughout the cycle
• schedules with a short (less than 10 days) second phase
• graphs with a high temperature in the second phase of the cycle for more than 18 days, without the onset of menstruation and a negative pregnancy test
• unexplained bleeding or heavy discharge mid-cycle
• heavy menstruation lasting more than 5 days
• graphs with a temperature difference in the first and second phases of less than 0.4 degrees
• cycles shorter than 21 days or longer than 35 days
• charts with clearly defined ovulation, regular intercourse during ovulation and no pregnancy occurring for several cycles

Signs of probable infertility according to the basal temperature chart:

• The average value of the second phase of the cycle (after the temperature rise) exceeds the average value of the first phase by less than 0.4°C.
• In the second phase of the cycle, there are temperature drops (the temperature drops below 37°C).
• The rise in temperature in the middle of the cycle continues for more than 3 to 4 days.
• The second phase is short (less than 8 days).

Determining pregnancy by basal temperature

The method of determining pregnancy by basal temperature works provided there is ovulation in the cycle, since with some health problems the basal temperature can be elevated for an arbitrarily long time, and menstruation may be absent. A striking example of such a disorder is hyperprolactinemia, caused by increased production of the hormone prolactin by the pituitary gland. Prolactin is responsible for maintaining pregnancy and lactation and is normally elevated only during pregnancy and lactation (see Examples of graphs for normal conditions and various disorders).

Fluctuations in basal temperature in different phases of the menstrual cycle are due to different levels of hormones responsible for phases 1 and 2.
During menstruation, basal temperature is always elevated (about 37.0 and above). In the first phase of the cycle (follicular) before ovulation, the basal temperature is low, up to 37.0 degrees.
Before ovulation, basal temperature decreases, and immediately after ovulation it increases by 0.4 - 0.5 degrees and remains elevated until the next menstruation.

In women with different lengths of the menstrual cycle, the duration of the follicular phase is different, and the length of the luteal (second) phase of the cycle is approximately the same and does not exceed 12-14 days. Thus, if the basal temperature after the jump (which indicates ovulation) remains elevated for more than 14 days, this clearly indicates pregnancy.

This method of determining pregnancy works provided there is ovulation in the cycle, since with some health problems the basal temperature can be elevated for an arbitrarily long time, and menstruation may be absent. A striking example of such a disorder is hyperprolactinemia, caused by increased production of the hormone prolactin by the pituitary gland. Prolactin is responsible for maintaining pregnancy and lactation and is normally elevated only during pregnancy and lactation.

If a woman is pregnant, then menstruation will not occur and the temperature will remain elevated throughout pregnancy. A decrease in basal temperature during pregnancy may indicate a lack of hormones that maintain pregnancy and the threat of its termination.

When pregnancy occurs, in most cases, implantation occurs 7-10 days after ovulation - the introduction of a fertilized egg into the endometrium (the inner lining of the uterus). In rare cases, early (before 7 days) or late (after 10 days) implantation is observed. Unfortunately, it is impossible to reliably determine the presence or absence of implantation either on the basis of a chart or with the help of ultrasound at an appointment with a gynecologist. However, there are several signs that may indicate implantation has taken place. All these signs can be detected 7-10 days after ovulation:

It is possible that small discharge appears these days, which disappears within 1-2 days. This may be so-called implantation bleeding. When the egg implants into the inner lining of the uterus, the endometrium is damaged, which leads to minor discharge. But if you experience regular discharge in the middle of the cycle, and pregnancy does not occur, then you should contact a gynecology center.

A sharp decrease in temperature to the midline level for one day in the second phase, the so-called implantation retraction. This is one of the signs most often observed in charts with confirmed pregnancy. This retraction can occur for two reasons. Firstly, the production of the hormone progesterone, which is responsible for raising the temperature, begins to decrease from the middle of the second phase; with pregnancy, its production resumes again, which leads to temperature fluctuations. Secondly, during pregnancy, the hormone estrogen is released, which in turn lowers the temperature. The combination of these two hormonal shifts leads to the appearance of implantation retraction on the graph.

Your chart has become three-phase, which means that you see a rise in temperature on the chart, similar to ovulation, during the second phase of the cycle. This rise is again due to the increased production of the hormone progesterone after implantation.

The example graph shows implantation retraction on the 21st day of the cycle and the presence of the third phase, starting from the 26th day of the cycle.

Early signs of pregnancy such as nausea, tightness in the chest, frequent urination, intestinal upset or just the feeling of pregnancy also do not provide an accurate answer. You may not be pregnant if you have all of these signs, or you may be pregnant without any symptoms.

All these signs can be a confirmation of pregnancy, but you should not rely on them, since there are many examples in which the signs were present, but pregnancy did not occur. Or, conversely, when pregnancy occurred there were no signs. The most reliable conclusions can be drawn if there is a clear rise in temperature on your chart, you had sexual intercourse 1-2 days before or during ovulation, and your temperature remains high 14 days after ovulation. In this case, the time has come to take a pregnancy test, which will finally confirm your expectations.
Measuring basal temperature is one of the main methods of tracking fertility, recognized by the World Health Organization (WHO). You can read more about this in the WHO document “Medical eligibility criteria for the use of contraceptive methods” page 117.
When you use the basal temperature method to protect against unwanted pregnancy, you need to take into account that not only the days of ovulation according to the basal temperature schedule can be dangerous. Therefore, during the period from the beginning of menstruation until the evening of the 3rd day after the rise in basal temperature, which occurs after ovulation, it is better to use additional measures to prevent unwanted pregnancy.

Attention! Making any diagnoses based solely on basal temperature charts is impossible. Diagnoses are made based on additional examinations performed by a gynecologist.