Ideal pregnant BT schedule. Basal temperature chart with examples and explanation

The concept of basal temperature (BT) is probably known to every woman who was planning a pregnancy. Monitoring this indicator makes it possible not only to accurately find out the day of ovulation, but also to diagnose an “interesting situation” even before the onset of a missed period.

What should a basal temperature chart look like if you are pregnant - example

As you know, basal is usually called the lowest temperature that the body normally reaches. This occurs during long (at least 4-6 hours) sleep, usually at night. It is measured in the mouth, vagina or rectally. This indicator changes on different days and periods of the menstrual cycle. For example, before ovulation it increases, and at the beginning of a new cycle it decreases. To see dynamics, you should measure them at the same time. It is recommended to do this immediately after waking up, while remaining in bed (movement increases the temperature). You can use a regular thermometer, but you need to hold it for at least 7 minutes. The data must be entered into the chart immediately. Measurements are taken daily, including on menstruation days. The data is affected not only by hormones, but also by physical activity, illness, taking medications or alcohol, and changing diet.

To get the correct schedule, which will be as informative as possible, and therefore useful when planning a child, you need to track this indicator for at least three to six months in a row.

In the first days of the menstrual cycle, in an ordinary healthy woman of reproductive age, the basal temperature remains within 36.4-36.7 degrees. Then it gradually decreases slightly to 36.3. At this temperature, an egg matures in a woman’s body. From approximately day 14 (the beginning of the second phase of the cycle), BT begins to rise again. It increases on average by half a degree. On the day of ovulation, this figure rises and reaches approximately 37 degrees. Increased BT persists for approximately 12 days. The hormone progesterone, which is intensively generated by the female body at this time, is responsible for such hyperthermia. If there was no conception, then the amount of progesterone decreases. Accordingly, the temperature begins to decrease. Before menstruation, it reaches the level of the first days of the cycle - 36.4-36.7 degrees. It stays this way during menstruation and for several days after it. This is an approximate two-phase graph of the basal temperature of a woman with a 28-day cycle who has no health problems. There may be some minor deviations associated with the individual characteristics of the body.

If conception has occurred, then BT remains at 37-37.4 degrees. This is how you can guess about the onset of pregnancy even before the delay appears. A week after ovulation, the temperature may temporarily decrease slightly as the egg attaches to the endometrium. After this it will rise again. This indicator remains at approximately 37 degrees in the early stages of pregnancy. After 20 weeks, a slight decrease is possible.

Basal temperature chart during twin pregnancy

According to medical data, multiple pregnancies are extremely rare, but they can still be diagnosed using a basal temperature chart. In some women who become pregnant with twins, the so-called “third phase” can be detected on the graph, that is, another temperature jump, similar to what happens during ovulation. It occurs on days 20-29 of the cycle. Experts explain this phenomenon by the fact that such women have significantly higher levels of progesterone and the hormone hCG (chorionic gonadotropin, which is generated by chorion tissue 7-8 days after fertilization of the egg). True, such a fluctuation is not a guarantee of multiple pregnancy, but only indicates its greater likelihood.

What does the basal temperature chart look like during an ectopic or frozen pregnancy?

Many women who used BT monitoring when planning pregnancy continue to monitor this important indicator after conception. There is a theory that decoding the relevant data helps to recognize an ectopic or frozen pregnancy.

As already mentioned, the ideal graph of basal temperature after pregnancy during normal gestation shows the preservation of this indicator within the range of 37 to 37.4 degrees. This should be the case for almost the entire nine months. If after a short time it decreases, for example, to 36.8, then this may be a signal of premature termination of pregnancy. The temperature drops because the female body reduces the production of the hormone progesterone. It is worth mentioning that there is a high probability that the freezing of the embryo will not affect the basal temperature chart in any way. For some time, it may remain unknown to the woman that the pregnancy is no longer developing, because fading (especially at the very beginning) is not always accompanied by obvious symptoms, such as bleeding. Only a doctor can make an accurate diagnosis.

It often happens that the schedule is normal, but the pregnancy is ectopic. Therefore, this criterion alone cannot serve to make a diagnosis. If, based on data from the BT chart or changes in her health, a woman thinks that she is pregnant, even if the pharmacy test result is negative, then it is better to contact your doctor and undergo the necessary tests. This way you can confirm your guesses and exclude possible pathologies.

Especially for -Ksenia Boyko

The method of measuring basal temperature is very popular among women. It is used both as one of the methods of contraception, and, on the contrary, in order not to miss ovulation. During pregnancy, basal temperature can become one of the early signals of pathology.

Basal is the temperature in the rectum. It may be slightly higher than the temperature in the armpit by a few tenths of a degree or coincide with it. In men, this indicator is more or less stable, in women it fluctuates depending on the phase of the menstrual cycle or pregnancy.

It should be remembered that basal temperature indicators have a wide range of individual differences, so this method becomes most informative when measured daily.

A single increase or decrease in temperature has no diagnostic value. This is why many ladies keep a basal temperature chart for several months or years.

How to measure it?

For measurements, a special rectal thermometer is used, which can be electronic or mercury. The readings of a mercury thermometer are considered more accurate, but an electronic one is safer to use.

You can also use a regular thermometer, but it is less convenient. The device is inserted into the anus 2-3 cm, the temperature measurement time is 5-7 minutes. During the procedure, you need to lie on your side, it is advisable to avoid unnecessary movements.

Temperature is measured in the morning (best before 8 o’clock), with the same thermometer at the same time. This is very important to ensure that the results remain informative.

These rules are the same for women of any age in all phases of the cycle and during pregnancy at any stage. It is not necessary to observe the measurement time to the nearest minute; deviations of half an hour will not significantly affect the result.

The observation period for basal temperature is 4 menstrual cycles or more. Only in this case is it possible to draw any conclusions from the information received, calculate the individual range of fluctuations during the cycle, and judge possible pathology, if it has arisen.

For the data to be reliable, you need to put a thermometer next to you when you go to bed, set an alarm clock, and measure your temperature immediately upon waking up. Then you need to write down the result (you can immediately put a notepad and pen next to the thermometer), after which you can go back to bed.

Any disease accompanied by an increase in body temperature (including a mild cold), alcohol, or having sex the day before can distort the results.

During pregnancy, the most valuable information is provided by indicators in the early stages (1-2 weeks), then their significance decreases.

Basal temperature chart during pregnancy before delay

Despite the fact that BT values are individual, there are general trends that can be used to track the processes occurring in the female reproductive system. The lowest temperature is observed in the last days of menstruation and immediately after it.

Then, throughout the first phase of the cycle, a gradual increase in BT occurs, the maximum occurring on days 2-3 after ovulation. Immediately before the release of an egg ready for fertilization, the temperature may drop (not observed in all women). Then it slowly decreases.

If conception occurs after ovulation, then the graph curve will go down sharply when it should be at its peak, low values will remain for several days, then a systematic increase in basal temperature will begin. This is one of the early signs of pregnancy, allowing you to determine it before the delay.

Additional signs will help to more accurately determine the onset of pregnancy - bloody vaginal discharge a little earlier than the expected period (implantation bleeding), a slight deterioration in well-being. All these signs occur before the delay, but may not be pronounced.

Basal temperature chart during pregnancy

As already mentioned, the most informative chart is the basal temperature in the first 2 weeks (before the delay). But sometimes there is a need to measure this indicator within 12 weeks or before birth.

Measuring BT is a simple, accessible and minimally invasive way to monitor the condition of the fetus. It is not accurate enough, but it allows you to observe the development of the unborn baby over time and identify pathologies in time.

The rules for measuring in the early stages remain the same as before pregnancy. It is necessary to record the indicators in the morning, at the same time, immediately after waking up, but without getting out of bed (to do this, put a thermometer, a notepad and a pen next to your sleeping place), be sure to build a graph for clarity and take measurements every day.

Starting from the third week (when the delay becomes obvious), the temperature remains consistently high. Despite the fact that the norm in this case is relative, if the thermometer shows less than 37°, then you should consult a gynecologist.

In the future, a consistently high level of basal temperature remains; normally it ranges from 37° to 38°; if the value is higher or lower than the specified corridor, this may be an alarming sign.

A slight decrease is possible at week 11, but not necessary. Here, the lower limit of normal is considered to be 36.9°.

In the twelfth week, the indicators return to the values of previous periods. At later stages, BT measurements are usually not carried out, although the gynecologist may recommend continuing the procedure if there is a risk of premature termination of pregnancy.

If a woman continues measurements before giving birth, she may notice that BT begins to increase 1-2 days before the baby is born. But in this case, there are more obvious signs and precursors that appear earlier and are more informative.

Increased or decreased basal temperature - what does it mean?

Despite the fact that normal BT levels vary from person to person, there is a range of values within which fluctuations do not pose a threat to the health of the mother and baby.

As already mentioned, this is 37-38°. During some periods of pregnancy, the temperature rises, at others it drops, but if it remains within the specified limits, there is nothing to worry about.

If BT drops below 37°, this indicates possible pregnancy pathologies - progesterone deficiency, missed abortion or threatened miscarriage.

A diagnosis based on one sign is not accurate, but if a woman notices such a feature, she needs to tell the gynecologist about it. Particularly dangerous is a sharp drop in BT below the normal value.

High internal temperature (above 38°) is an indicator of the inflammatory process. In this case, it is accompanied by an increase in general body temperature, general malaise, and other symptoms of the disease.

But there is another reason for increased indicators - incorrect measurement or physical activity before the procedure, errors in diet, or having sex. Therefore, if BT remains high, but the woman feels well, there is nothing to worry about.

In general, it is important to remember that a single change in the indicator, even if it is outside the normal range, is not dangerous; a sign of pathology is a persistent decrease or increase in BT for 4-5 measurements in a row.

Examples of basal temperature charts during pregnancy

This is what the basal temperature graph looks like before the delay is normal:

In this graph you can clearly see all three phases of BT change. Phase 1 is the normal first half of the cycle before ovulation, the second corresponds to ovulation and conception, the third is implantation retraction and a subsequent increase in temperature, by which pregnancy can be determined before the delay.

On the graph, the letter M marks the days of menstruation, O – ovulation, B – the time when pregnancy is determined.

Some more examples of basal temperature charts can be seen below.

A few more additional tips for determining basal temperature are in the next video.

More and more women are taking a more conscious approach to conceiving and having a child. Infantilism towards the family is becoming less and less, and children appear in families that are truly ready for this.

Medicine has made great progress: now you can learn about most pathologies in the early stages of pregnancy and predict many undesirable consequences. Example - married couples with problems conceiving are offered IVF procedure. In general, the process of pregnancy and birth is, if desired, maximally controlled by medical staff. The birth of a healthy and strong baby, subject to the recommendations of doctors, is a normal trend in modern society.

So, after deciding to get pregnant, many women visit various specialists to check their health and the health of the future father. If the result is positive, it is worth further monitoring the fertile days of immediate conception. And here there are many options.

With a stable menstrual cycle, it is enough to simply find out the days of ovulation. But due to many characteristics of the body, life stresses, periods come irregularly. This makes conception significantly more difficult, turning it into a roulette wheel.

You can buy an ovulation test at the pharmacy; its operating principle is similar to a regular pregnancy test. But again, without knowing the exact date, several tests may be required - and this is very expensive. And you can also determine the right days by donating blood. This method is quite effective, but it is not suitable for everyone.

One of the most accurate methods for determining ovulation is the method of measuring basal temperature. As an example, it allows you to determine not only fertile days, but also the presence or absence of ovulation, evaluate the functioning of the ovaries, find out about future pregnancy, and track it up to twelve to fourteen weeks. The BT schedule for a pregnant woman in the early stages is the most convenient means of monitoring embryo development.

Basal temperature is temperature, measured rectally with a thermometer, orally or vaginally at rest after a night's sleep. Temperature tends to change during the menstrual cycle. Using a graph of this temperature, you can analyze the state of the body and the readiness to bear a child.

The principle of measuring a temperature graph is based on two phases:

follicular;
luteal

In the first phase, from the end of menstruation until the beginning of ovulation, the egg matures in the body. The temperature at this time is in the range of 36-36.5 degrees, its duration is directly related to the maturation of the egg. For some, this process may take ten days, for others twenty - for each woman the time frame is strictly individual. The day before ovulation, basal temperature drops by several tenths of a degree. On the day the egg is released, its direct maturation, there is a jump to 37-37.2 degrees. This is due to the surge of the hormone progesterone. Basal temperature does not drop throughout the luteal phase, and estrogens are gradually replaced by progesterone.

The best time to conceive should be considered third - fourth day before ovulation begins and and days after ovulation. At this time, the life cycles of the male and female cells develop most successfully: the sperm still remain viable, and the egg is ready to merge with them. If no unification occurs at this time - the egg dies. Accordingly, another menstrual cycle is required for a new attempt at conception.

The second phase, as mentioned earlier, is marked by the replacement of estrogen with progesterone. Progesterone is produced by the corpus luteum, which replaces the burst follicle from which the egg was released. The corpus luteum consists of luteal pigment and lipids, and it is this that produces progesterone before the placenta matures during pregnancy. Progesterone helps the uterus accept the emerging embryo.

The luteal phase takes place within sixteen to twelve days and the normal basal temperature does not fall below 37 degrees. If pregnancy does not occur, then a day or two before the start of menstruation, the temperature drops by two to three tenths of a degree. Next, the unfertilized egg is released with a layer of endometrium.

Luteal phase disturbance often indicates about female infertility. Mostly, the causes of disorders and lack of pregnancy are stress and inflammatory processes in the uterus.

The optimal difference between the phases is considered to be from four to five tenths of a degree.

Correct measurement

You need to measure your basal temperature correctly in the morning after sleep at the same time. You should not make sudden movements, so it is better to prepare the thermometer in advance, wash it, lower the degrees and leave it next to your sleeping place. Having chosen a certain measurement method, you should stick to it throughout the entire pregnancy. If a pregnant woman changes the method, the basal temperature chart data may be incorrect. Five to seven minutes is enough for daily measurement. Optimal data will be obtained if you start measuring temperature on the sixth day after the start of menstruation.

The BT chart can be kept on paper, but it is much more convenient to keep it on the Internet. There are many programs that make it easy to find out about the favorable time for conception. In women's communities you can easily find a link to the desired application. Further difficulties lie only in measuring the temperature correctly. Transfer the numbers to the BBT chart and maintain it throughout the entire cycle - the program itself will display the time of ovulation and calculate average temperature between phases.

You should not take into account in the BT schedule days when the temperature is elevated due to illness or other factors. If you had to get out of bed at night, your basal temperature should be measured no earlier than five to six hours later. Otherwise, the schedule will obviously be incorrect.

It is much easier to measure normal body temperature rather than basal body temperature. But it is important to remember that BBT can change depending on cold, heat, stress and other factors. And accordingly, the resulting figures will not be correct. Basal temperature should be measured only after a long sleep, at rest. Previously need to wash the thermometer.

Bt during pregnancy, its schedule

If, during the measurement of basal temperature, it suddenly turns out that conception has occurred, under no circumstances should you stop maintaining the pregnant woman’s schedule. Right now it is very important to control the correct development of the embryo A.

At this time, it remains at around 37 degrees, the permissible deviation ranges from one tenth to three tenths. If the temperature drops over several days, the unborn child is at risk. This occurs from insufficient progesterone production. In this case, you should immediately consult a doctor and be examined using an ultrasound machine.

Elevated temperature is also not a good thing; most likely, the expectant mother has some kind of inflammation. However, a one-time increase or decrease in basal temperature should not be considered critical; this value can be obtained erroneously or due to stress.

After three months of pregnancy, basal temperature no longer carries an informative load. By this time, the pregnant woman’s body has almost completely changed and the corpus luteum transfers the production of progesterone to the placenta. Therefore, pregnant women no longer need to maintain a BT schedule.

When a pregnant woman fills out a chart, there are several intervals by which the progress of conception can be judged:

A week after ovulation, the temperature drops by an average of half a degree: at this time, the embryo first tries to gain a foothold in the endometrium. The expectant mother may observe slight bleeding at this time;
The entire luteal phase passes with a bt level above 37 degrees;
Before the date of menstruation, the temperature adds another three tenths of a degree, thus, the third phase of pregnancy can be detected;
After the expected date of the onset of menstruation, the basal temperature lasts up to 16 days. Until this period, it is worth continuing measurements and after this, you can do a pregnancy test. There is a high probability that the test will be positive. “My bt schedule has entered the third phase!” A woman may be preparing to become a mother.

Increased and decreased bt

Pregnant schedules with a smooth increase from phase to phase are considered ideal. Tangible dips and irregularities indicate problems in the female body. Therefore, you need to contact a specialist for a health check. The most important indicator is the discrepancy between the phases of at least four tenths of a degree. If this fact is observed, there is no need to worry.

To summarize, charting your basal temperature is an example of effective fertility control. In addition to the accuracy of the data, the BT method is good about lack of drug intervention. After all, every woman ultimately wants to tell her husband: “Hurray, my schedule is pregnant, it showed that I’m pregnant!”

Attention, TODAY only!

Just 15 years ago, measuring BT was considered one of the main diagnostic methods for assessing women's reproductive health. After all, the basal temperature of a non-pregnant woman is fundamentally different from the BT of a pregnant woman. A “healthy” temperature chart is completely different from that of a girl with “feminine” problems.

Now this method has given way to other, more modern and accurate diagnostic methods. Gynecologists prefer to prescribe ultrasound and hormonal tests for patients. However, the BT method can still tell a lot both to the girl herself and her doctor.

unsuccessful attempts to conceive a child over a long period of time;
suspicion of hormonal imbalance and changes in the menstrual cycle;
probable infertility of one of the partners;
calculation using a chart of the most favorable days for conception, when ovulation occurs (the release of an egg ready for fertilization from a mature follicle);
control over the processes occurring in a woman’s body;
diagnosis of anovulatory cycles.

BT is measured in the morning, after a full night's rest (when healthy sleep lasted at least 6-7 hours), in a state of complete rest and without getting out of bed. As a rule, the most accurate results can be obtained if you measure basal temperature with a regular mercury thermometer in the rectal passage, but experts also do not deny the information content of measurements obtained by measuring indicators in the oral cavity or vagina.

Based on the results of which a special schedule is drawn up. Only a qualified specialist can give a competent assessment of the basal temperature chart. However, the girl herself can understand a lot.

Cycle phases on the chart

The normal monthly cycle of a woman who is not pregnant consists of two main periods: the follicular and luteal phases. In the first phase of the cycle, which begins with the onset of menstruation, the woman’s body actively synthesizes estrogen hormones, which have a positive effect on the maturation of the egg and the proliferation of the uterine endothelium. This period is characterized by consistently low BT indicators on the graphs, and therefore is called hypothermic.

Approximately in the middle of the monthly cycle, an egg matures in the follicle. Its release from the ovary or ovulation is accompanied by a change in the woman’s hormonal levels, after which progesterone, the main hormone of pregnancy, normally begins to be produced. This biologically active substance, influencing thermoregulation centers in the brain, provokes an increase in temperature by about 0.4-0.6 degrees. If fertilization does not occur, progesterone levels begin to decrease, menstruation begins and the body again enters the follicular phase of the cycle.

Temperature norm

Basal temperature in the absence of pregnancy has its own characteristic features, which are clearly visible on correctly drawn up graphs of the period without conception. The norm is when in the first phase the temperature ranges from 36.3 to 36.6, and in the second it increases by about 0.4-0.6 and is already 36.9-37.1 degrees and higher.

So, what should be the basal temperature for non-pregnant women? The following features are typical for a non-pregnant basal temperature chart:

decrease in BT with the onset of menstruation to a level of 36.3-36.5;
stable level of basal temperature throughout the follicular phase;
an increase in BT levels approximately two weeks before the expected menstruation;
the presence of ovulation relapse or a decrease in basal temperature by 0.1 before the release of the reproductive gamete from the ovary;
increase in indicators during ovulation to 36.9-37.1;
the temperature difference between the two phases should not exceed 0.4-0.5;
decrease in temperature level to 36.7-36.8 one or two days before the start of menstruation.

Naturally, the graph of basal temperature in the absence of pregnancy differs in many ways from the curves obtained as a result of measuring BT in women who are already carrying a baby.

The main feature of schedules without pregnancy is a decrease in temperature levels in the last few days of the cycle, that is, a decrease in progesterone activity. In addition, the basal temperature, if there is no pregnancy (unlike the indicators of women expecting a child), has a two-level appearance, falling in the middle of the cycle and a gradual rise in the temperature curve in its second period.

Deviations from the norm

Each woman normally experiences menstrual cycles without the release of a mature egg, which are called anovulatory, approximately twice a year. On such charts, the line is constantly at the same level, without dips or sharp rises. Anovulatory cycles are characterized by the following features:

absence of a difference in basal temperature in the middle of the cycle on the graphs. The situation when is confirmation of the absence of ovulation;
in the second phase, no increase in temperature level is recorded, since pregnancy does not form, synthesizing progesterone.

Basal temperature charts will allow you to suspect some diseases of the female genital area. Temperature jumps above 37.0 in the first phase of the cycle indicate the development of an inflammatory process in the ovaries or uterus. And if there is a lack of hormones, a relative increase in it will be recorded in the first period of the cycle and a decrease in the second.

However, it is important to remember that any deviations from the norm on the graph are just a reason to contact a specialist. Temperature measurement itself is only an auxiliary, and not the main diagnostic method. Perhaps your fears are completely unfounded. Much more reliable are laboratory tests, ultrasound and other studies that your doctor will prescribe.

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 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.

You should measure your basal temperature every day if possible, including on your period.

Measurements can be taken 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.

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

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.

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 BBT before that, otherwise, at your usual 8 o’clock it will no longer be informative.

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.

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.

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

It is best to immediately record your basal temperature after measurement. 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.

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

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

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.

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.

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

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, she went to bed at 3 o’clock and measured it at 6), taking sleeping pills, stress, etc.

All factors that in one way or another could 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, in general, The 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.

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.

Characteristically, the temperature drops before menstruation and rises with the beginning of the next cycle. If there is no drop in temperature before the start of menstruation in the first cycle, i.e. the temperature remains at this level, then pregnancy can be assumed, despite the bleeding that has begun. Take a pregnancy test and contact a gynecologist who will perform an ultrasound to make an accurate diagnosis.

If the basal temperature in the first phase rises sharply for one day, then this does not mean anything. Inflammation of the appendages cannot begin and end in one day. Also, a lack of estrogen can only be assumed by assessing the entire graph, and not a separate temperature in the first phase. For diseases accompanied by high or elevated body temperature, measuring basal temperature, much less judging its nature and analyzing the graph, makes no sense.

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 ovulation is stimulated, in particular by clomiphene (clostilbegit) with the use of duphaston in the second phase of the cycle, 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.

Our regular reader, Natalya Gorshkova, has compiled a form for you to quickly fill out and automatically plot your basal temperature chart, which you can print out and show to your doctor. You can download it from the link: schedule form.

The charts are discussed on the forum

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