Basal temperature (BT) is the most low temperature human body, measured at rest. Determining the level of basal temperature allows you to predict the onset of ovulation and determine pregnancy at its earliest stages. The technique is also included in the scheme of natural regulation of conception and is used to identify various gynecological diseases.

Measurement Rules

When determining basal temperature, you must adhere to certain rules, otherwise the data obtained may be misinterpreted:

  1. BT is determined only in the rectum. Measuring temperature in the armpit or mouth does not give reliable results.
  2. Measurements are taken in the morning, without getting out of bed, before any physical activity. For convenience, keep a thermometer handy.
  3. Before starting the study, you must have at least 4 hours of restful, uninterrupted sleep.
  4. BT measurement is carried out with an electronic thermometer - the same one. You can use a mercury thermometer, but with great caution.
  5. The study should take place at approximately the same time of day. Deviations of 30-60 minutes in any direction are allowed.
  6. The research time is at least 5 minutes.
  7. There is no break during menstruation.

The obtained data is entered into a table daily. In the future, based on the identified results, it will be possible to draw certain conclusions. To assess the menstrual cycle and identify gynecological pathology, it is recommended to measure basal temperature for at least 3 months in a row. It is advisable to start the study on the first day of the menstrual cycle (i.e., the first day of menstruation).

Is it possible to measure basal temperature during the day? Yes, after 4 hours of sleep. Unfortunately, such results are often unreliable, so relying on them is not recommended. If a woman works a night shift, she can conduct research during the day, provided that this is her usual, practically unchanged work and rest schedule for many months.

Indications for measuring basal temperature

The study is carried out in the following situations:

  • Menstrual irregularities (if hormone imbalance is suspected).
  • Diagnosis of pregnancy in the early stages.
  • Determining the time of ovulation.
  • As part of the MRP (fertility recognition method as a natural method of contraception).
  • Grade hormonal levels for some gynecological diseases (including infertility).

In most cases, measuring basal temperature is prescribed when planning pregnancy and identifying the causes of infertility. This examination will also be useful when searching for factors leading to menstrual irregularities (delayed menstruation, lengthening or shortening of the cycle, etc.).

Basal temperature measurement is not carried out in the following situations:

  • If a woman does not have the opportunity to measure her temperature at approximately the same time (special work schedule, etc.).
  • In the presence of acute inflammatory processes or exacerbation of chronic pathology, leading to an increase in general body temperature.

In the latter case, the research will be uninformative. It is recommended to wait for recovery and only then return to measuring basal temperature.

Important aspects

There are factors that influence the level of basal temperature:

  • poor sleep (frequent awakenings, need to get up in bed at night);
  • stress;
  • diseases of the digestive tract (including diarrhea);
  • ARVI (even without fever in the armpit);
  • drinking alcohol;
  • intimacy;
  • long flights;
  • change of time zones, climate;
  • taking medications (including hormonal, sedatives, sleeping pills).

All of these factors should be noted in the table and taken into account when interpreting the results.

Basal temperature and menstrual cycle

Determining basal temperature plays a big role in assessing a woman’s menstrual cycle. Let's consider the change in parameters using the example of a normal 28-day female cycle.

The first (follicular) phase of the menstrual cycle lasts from days 1 to 14 and is influenced by estrogen. At this time, the follicles mature and the dominant one is released among them. The BT level during this period remains between 36.1 and 36.7 °C.

Ovulation in a 28-day cycle occurs on days 13-14. The maturation and release of the egg coincides with the peak level of LH (luteinizing hormone). The day before ovulation, basal temperature drops by 0.5 °C. Immediately at the moment of ovulation, BT rises again, reaches 37.0 - 37.4 ° C and remains at this level throughout the second phase of the cycle.

The second (luteal) phase occurs under the influence of progesterone. The endometrium grows, preparing for possible implantation ovum. If fertilization does not occur, a corpus luteum forms at the site of the burst follicle. From days 14 to 28 of the cycle, the basal temperature remains above 37.0 °C. A decrease in indicators occurs only before menstruation, 24-48 hours. During monthly bleeding, BT remains low (from 36.1 to 36.7 °C).

Basal temperature and pregnancy

If a child is conceived, the basal temperature remains high throughout the first trimester. It stays at 37.0 - 37.4 °C, and only after 14 weeks begins to gradually decrease. In the II and III trimesters, the basal temperature is fixed within 36.4-36.7 °C.

An increase in basal temperature during pregnancy indicates the following conditions:

  • inflammatory process in the appendages and uterus, pelvic organs, intestines;
  • general infectious process.

Low basal temperature occurs in the following situations:

  • threat of miscarriage;
  • incipient miscarriage;
  • regressing pregnancy.

In all these situations, there is a decrease in progesterone levels, which determines the change in basal temperature. Any deviations from the norm should be reported to your doctor.

Decoding the results

By correctly measuring basal temperature, a woman can find answers to the most important questions:

  • Is the menstrual cycle normal and are there any abnormalities?
  • Are follicles maturing and should ovulation be expected?
  • Was there ovulation in this cycle, and on what day did it occur?
  • Has the child been conceived or should the onset of menstruation be expected (you can determine its arrival 24-48 hours before the start of bleeding).

Deviations from the normal schedule make it possible to suspect endocrine pathology, suggest the causes of infertility and timely identify some complications that arise in the early stages of pregnancy.

Normal indicators

To assess the menstrual cycle, it is necessary to chart your basal temperature for at least three consecutive months. The graph is lined up on a sheet of paper in a box. A coordinate axis is drawn, where the basal temperature indicators will be vertically, and the days of the cycle will be horizontally. Each day of the cycle will have its own mark on the chart - the level of basal temperature. Below, under each day of the menstrual cycle, factors that could affect the temperature (stress, sexual intercourse, illness, etc.) must be indicated.

Normal indicators of the menstrual cycle:

  • The total length of the cycle is 21-35 days (from the first day of one menstruation to the first day of the next).
  • The duration of the second phase of the cycle is always 12-14 days.
  • The duration of the first phase of the cycle may vary. Its minimum duration is 7 days.

Normal basal temperature values ​​are presented in the table:

Temperature curve options

There are several types of graphs when measuring BT:

Type I

Features:

  • There is a stable increase in BT in the second phase of the cycle by at least 0.4 °C.
  • There is a preovulatory and premenstrual decrease in BT.

This schedule corresponds to a normal two-phase menstrual cycle (it was discussed in detail above).

Type II

Features:

  • There is a slight increase in BT in the second phase of the cycle: no more than 0.2-0.3 °C.
  • The duration of the second phase is 12-14 days.
  • There is a slight preovulatory and premenstrual decrease in BT.

Such a schedule indicates estrogen-progesterone deficiency and requires mandatory examination by a doctor. It is necessary to evaluate the level of major hormones in each phase of the cycle and find out the reason for such changes. This condition often threatens infertility.

III type

Features:

  • There is an increase in BT in the second phase of the cycle shortly before the onset of menstruation by 0.4 °C.
  • The second phase lasts less than 10 days.
  • There is no premenstrual decrease in BT.

This graph indicates insufficiency of the second phase of the cycle (luteal insufficiency) and indicates low progesterone levels (absolute or relative with high estrogen concentrations).

Possible causes of second phase failure:

  • Ovarian pathology: resistant or exhausted ovarian syndrome, ovarian hyperinhibition syndrome, polycystic ovary syndrome, etc.
  • Thyroid diseases.
  • Pathology of the pituitary gland: hyperprolactinemia, pituitary hypogonadism.
  • Organic diseases of the genital organs: endometriosis, endometrial hyperplasia, uterine fibroids, polyps, tumors.
  • Inflammatory diseases of the uterus and appendages: endometritis, salpingoophoritis.
  • Pathology of other organs: hepatitis, cirrhosis of the liver, etc.
  • Condition after abortion, curettage of the uterine cavity for other reasons.
  • A sharp decrease in body weight (prolonged fasting, diets, diseases of the digestive tract).
  • Severe stress.
  • Abrupt changes in climate and time zones.
  • Redundant physical activity.
  • Taking narcotic drugs.

Insufficiency of the luteal phase threatens infertility or miscarriage. To correct this condition, it is necessary to find out the cause of the failure. Hormonal therapy is carried out according to indications. During pregnancy, progesterone supplementation is necessary.

IV type

A monotonic curve is noted on the graph: BT remains within the range of 36.1 - 36.7 °C throughout the entire cycle. There is no ovulation. This cycle is considered anovulatory.

The anovulatory cycle is a variant of the norm. It is believed that every healthy woman can have 1-2 cycles a year without ovulation. With age, the number of anovulatory cycles increases. During puberty and the onset of menopause, most cycles pass without ovulation. Conceiving a child this month is impossible.

Frequent anovulatory cycles in women of reproductive age are a pathology. The cause may be various endocrine diseases, ovarian pathology, etc. For an accurate diagnosis and development of a treatment regimen, a complete examination by a gynecologist-endocrinologist is necessary.

V type

A chaotic temperature curve is observed. The range of indicators does not fit into any of the known options and does not lend itself to any logic. A similar schedule occurs with estrogen deficiency. The onset of pregnancy with estrogen deficiency is a big question.

A single chaotic schedule should not frighten a woman. Such a malfunction can occur under stress, climate change, or exacerbation of various extragenital diseases. If the schedule subsequently returns to normal, treatment is not required. A chaotic temperature curve for two or more months requires mandatory examination by a specialist.

Measuring basal temperature is easy and available method assessment of the state of the female reproductive sphere. Regular scheduling allows you to predict the onset of ovulation and menstruation, detect pregnancy in the early stages and identify menstrual irregularities. Determining the level of basal temperature is practiced in the diagnosis of endocrine infertility and other gynecological diseases.



Ovulation is a key event in a woman's menstrual cycle. If you accurately determine the day when it occurs, it is possible not only to plan conception, but also to slightly influence the gender of the unborn baby.

Various methods can be used to obtain information about when the egg leaves the ovary: ultrasound of the ovaries or determination of the concentration of sex hormones several times during the cycle. But the simplest and free method that every woman can carry out at home was and remains basal thermometry. A careful analysis of how basal temperature changes daily will make it possible to study the functioning of the ovaries, understand whether ovulation is occurring or not, and determine pregnancy earlier than a test can show it.

The essence of the basal thermometry method

A key role in controlling the female body is played by sex hormones: progesterone and estrogen, prolactin, gonadotropic hormones of the hypothalamus and pituitary gland. The balance between them is reflected in many processes, including body temperature, which is called basal.

Basal temperature is the lowest temperature indicator, indicating the actual temperature of the internal organs. It is determined immediately after rest (usually after a night’s sleep), before the start of any physical activity that will create measurement error. Only departments that communicate with body cavities are suitable for its establishment. These are the vagina (it is connected to the uterus), the rectum (it is directly connected to the large intestine) and the oral cavity, which passes into the oropharynx.

Set level basal rate hormones estrogen and progesterone. They “dictate” what basal temperature a particular woman should have during ovulation.

A normal amount of estrogen by itself does not affect the temperature. The task of this hormone is to prevent progesterone from affecting the thermoregulatory center located in the hypothalamus (this is an area associated with the brain).

In the first half of the cycle, estrogen “dominates”. It does not allow the basal temperature to rise above 37°C. During the period of ovulation, when initially an increased amount of estrogen enters the blood, there is a decrease in temperature by about 0.3°C. When the egg leaves the follicle, and in its place a corpus luteum appears, producing progesterone, the thermometer shows 37°C or more. In this case, the basal thermometry graph becomes similar to a bird with open wings, whose beak symbolizes the day of ovulation.

Further, when the corpus luteum dies (if conception has not occurred) and the amount of progesterone decreases, the temperature drops. During menstruation, the indicator stays at 37°C, then decreases and everything repeats all over again.

If pregnancy occurs, progesterone is normally produced more and more, so the temperature does not decrease, as before menstruation, but, on the contrary, increases.

What determines the day of ovulation

Knowing on what day the oocyte leaves the follicle, a woman can:

  • plan a pregnancy: after 3-4 months of charting, you can practice sexual intercourse not “approximately”, counting 14 days from the expected start of the next menstruation, but knowing exactly the day of ovulation;
  • plan the gender of the unborn baby (the method is not 100%). If you want a boy to be born, then it is better to plan sexual intercourse on the day of ovulation (on this day the basal temperature decreases and vaginal leucorrhoea takes on the color and consistency of raw chicken protein). If your dream is to give birth to a girl, it is better to have sex 2-3 days before expected ovulation;
  • knowing when ovulation occurs, you can, on the contrary, avoid conception, since a few days before it, the very day the egg is released and the day after are the most “dangerous” days;
  • the graph will show if there are hormonal problems, inflammation of the reproductive organs or lack of ovulation (), which is why conception does not occur.

In addition, drawing a basal thermometry graph in some cases will allow you to determine pregnancy without purchasing a test. And if you continue to manage it the first time after conception, you can see the threat of miscarriage in time and take the necessary measures.

How to properly perform basal thermometry

It is very important to know how to correctly measure basal temperature to determine ovulation. After all, a woman’s body is extremely sensitive to minimal changes in external conditions, and the units of measurement in which the graph is kept are tenths of a degree (this is where a fluctuation of 0.1-0.05°C can be important).

Here are the basic rules, if followed, the temperature graph will become as informative as possible:

  1. Measurements are taken either in the rectum (optimally), or vaginally, or in the mouth (for this you need a special thermometer).
  2. The thermometer needs to be inserted 2-3 cm and lie quietly while taking measurements for 5 minutes.
  3. Before taking measurements, you cannot sit down, spin around, stand up, walk, or eat. Even shaking the thermometer can lead to a false result.
  4. Choose a high-quality thermometer (preferably mercury) with which you will measure your temperature daily for 3-4 months.
  5. Place on a table (shelf) near the bed, which you can reach in the morning without getting up, 3 things: a thermometer, a notebook and a pen. Even if you start keeping your schedule on a computer - in online or offline programs, it is best, after reading the thermometer readings, to immediately write it down indicating the number.
  6. Take measurements every morning at the same time. Plus or minus 30 minutes.
  7. Before taking measurements, be sure to sleep for at least 6 hours. If you got up at night, take measurements later so that 6 hours have passed.
  8. Thermometry should be taken at 5-7 am, even if you can sleep until noon. This is explained by the daily biorhythms of the hormones of the adrenal glands and hypothalamus, which affect the basal temperature.
  9. The accuracy of measurements is affected by travel, alcohol consumption, physical activity, and sexual intercourse. Therefore, try to avoid these situations as much as possible during basal thermometry, but if they happen, mark them in the chart. And if you get sick and develop a fever, all measurements for the next 2 weeks will be completely uninformative.

When should you start measuring your basal temperature?

From the very first day of menstruation, that is, from the first day of the cycle.

How to keep a schedule?

You can do this on checkered paper by drawing 2 lines: on the horizontal line (along the x-axis) mark the day of the month, and draw the vertical line (y-axis) so that each box represents 0.1°C. Every morning, place a dot at the intersection of the thermometry reading and the desired date, and connect the dots. There is no need to take your temperature in the evening. Below the horizontal line, leave a place where you will write daily notes about the discharge and events that happened that could affect the indicators. Draw a horizontal line over the measurement results, starting from day 6 to day 12. It is called overlapping and serves for the convenience of deciphering the graph by the gynecologist.

We also suggest using ready-made template the basal temperature graph below by saving it to your computer and printing it out. To do this, move the cursor over the image and use the right-click menu to save the image.

Pay attention! If you are taking birth control, you do not need to take thermometry. These drugs specifically disable ovulation, which makes them contraceptive.

Read also about other methods for determining ovulation in ours.

What does the basal temperature graph look like during ovulation (that is, during a normal ovulatory cycle):

  • in the first three days of menstruation, the temperature is about 37°C;
  • by the end of menstruation, temperature indicators drop, amounting to 36.4-36.6°C;
  • further, within 1-1.5 weeks (depending on the length of the cycle), thermometry shows the same numbers - 36.4-36.6 ° C (can be lower or higher, depending on the metabolic processes in the body). It should not be the same every day, but fluctuate a little (that is, not a straight line is drawn, but zigzags). The 6 values ​​connected by an overlay line must be followed by three days in which the temperature is 0.1°C or more, and one of these days is above 0.2°C. Then after 1-2 days you can expect ovulation;
  • just before ovulation, the thermometer shows the basal temperature 0.5-0.6°C lower, after which it rises sharply;
  • during ovulation, the basal temperature is in the range of 36.4-37°C (according to other sources, above 37°C). It should be 0.25-0.5 (on average 0.3°C) higher than at the beginning of the menstrual cycle;
  • what the basal temperature should be after ovulation depends on whether conception has occurred or not. If pregnancy does not occur, the numbers gradually decrease, by a total of about 0.3°C. The most high temperature observed 8-9 days after the release of a mature oocyte. It is on this day that the fertilized oocyte is implanted into the inner uterine lining.

Between the average numbers of the two halves of the cycle - before and after ovulation - the temperature difference should be 0.4-0.8 ° C.

How long does basal temperature last after ovulation?

Before the onset of menstruation. Usually this is 14-16 days. If 16-17 days have already passed, and the temperature is still above 37°C, this most likely indicates pregnancy. During this period, you can do a test (the main thing is that 10-12 days have already passed after ovulation), you can determine hCG in the blood. Ultrasound and examination by a gynecologist are still uninformative.

These are indicators of the normal basal temperature during ovulation, as well as before and after it. But the menstrual cycle does not always look so perfect. Usually the numbers and type of curve raise many questions among women.

High numbers in the first phase of the cycle

If after menstruation the basal thermometry numbers are above 37°C, this indicates an insufficient amount of estrogen in the blood. In this case, an anovulatory cycle is usually observed. And if you subtract 14 days from the next menstruation, that is, look at phase 2 (otherwise it is not visualized), then you can see sharp jumps in temperature indicators, without their gradual increase.

The syndrome is accompanied by various unpleasant symptoms: hot flashes, headaches, heart rhythm disturbances, and increased sweating. This type of temperature curve, together with the determination of low levels of estrogen in the blood, requires the doctor to prescribe drugs - synthetic estrogens.

Progesterone and estrogen-progesterone deficiency

If after ovulation the basal temperature does not rise, this indicates progesterone deficiency. This situation is a common cause of endocrine infertility. And if conception does occur, then there is a danger of miscarriage early until the placenta forms and takes over the function of producing progesterone.

Insufficient functioning of the corpus luteum (the gland formed at the site of the opened follicle) is indicated by a decrease in temperature indicators already 2-10 days after ovulation. If the length of phase 1 of the cycle can still vary, then the second phase should be the same and average 14 days.

Progesterone deficiency can be assumed when the numbers increase to just 0.3°C.

If you already have a low basal temperature 2-3 cycles after ovulation, contact your gynecologist with this chart. He will tell you which days of the cycle you need to donate blood to determine progesterone and other hormones in it, and based on this analysis he will prescribe treatment. Usually, the administration of synthetic progesterones is effective, and as a result, the woman is able to become pregnant and carry a child to term.

Estrogen-progesterone deficiency

This condition, when the ovaries do not produce sufficient quantities of both hormones, is indicated by a temperature graph that does not have significant fluctuations (there are large areas with straight lines rather than zigzags). This condition is also indicated by an increase in temperature to only 0.3°C after ovulation.

Anovulatory cycle

If it is already the 16th day of the menstrual cycle, and there is no characteristic decrease and then increase in temperature, most likely there was no ovulation. The older a woman is, the more such cycles she has.

Based on the above, basal thermometry is a simple and inexpensive method of determining the optimal days for conception, as well as the reasons why pregnancy may not occur. It only requires 5-10 minutes of time in the morning. Whatever indicators you see in yourself, this is not a reason for panic or self-medication. Contact your gynecologist with your schedule several cycles in advance, and you will be prescribed a diagnosis and treatment.

Basal temperature.

Measuring basal temperature (BT) allows you to solve several problems:

1. check how correctly the ovaries secrete hormones according to the phases of the menstrual cycle;
2. determine whether the egg matures and when this happens (accordingly, highlight “dangerous” days for the purpose of protection or, conversely, the possibility of getting pregnant);
3. find out whether pregnancy has occurred in case of delay or unusual menstruation;
4. suspect the presence of endometritis - inflammation of the uterus.

Basal temperature, that is, the temperature measured in a woman’s anus, reflects fluctuations associated with changes in the tissue reactions of the internal genital organs depending on the production of certain hormones. These temperature fluctuations are local and do not affect the temperature measured, for example, in the armpit or mouth. However, a general increase in temperature as a result of illness, overheating, etc. naturally affects the BT indicators and makes them unreliable.

Therefore, the RULES FOR BT MEASUREMENT are quite strict:
1A. The temperature must be changed at approximately the same time on weekdays and holidays.
2A. You should prepare a medical thermometer in advance and place it in close proximity to the bed.
3A. Without getting up, without sitting down, without being particularly active in bed, take a thermometer and insert its narrow part into the anus.
4A. Lie still for 5 minutes.
5A. Remove the thermometer and record the reading in the table.

By the way, on the website babyplan.ru you can create your own schedule for each cycle.

Normally, BT has the appearance of a flying seagull: in the 1st half of the cycle it is below 37.0, and in the 2nd half it is higher. The NORMAL cycle schedule for a FERTILE woman has the following parameters (the average statistical cycle duration is taken as 28 days).

1B. From day 1 of the cycle until the end of menstruation, BT consistently decreases from approximately 37.0 to approximately 36.3-6.5.
2B. Until approximately the middle of the cycle (in longer cycles - approximately until the day 2 weeks before the start of the next menstruation), BT fluctuates between 36.3-36.6.
3B. 2 weeks before the start of the next menstruation, the EGG MATURATES, and therefore BT increases to 37.1-37.3 within 3-4 days. (In many women, before increasing for 1-2 days, BT may decrease by 0.1-0.2*).
4B. During phase 2, BT remains within the range of 37.0-37.4.
5B. 2-3 days before the start of menstruation, BT begins to decrease, reaching approximately 37.0 at the beginning of menstruation.
6B. The difference between the average BT of the second phase and BT of the first phase should be at least 0.4-0.5*.

Deviations can be varied, with each feature indicating certain violations.

1B. During menstruation, BT does not decrease, but increases - the presence of chronic endometritis (inflammation of the uterine mucosa), one of the causes of female infertility.
2B. In phase 1, BT is high (36.6 and above) - low content of estrogens (female sex hormones), the reason for the unripeness of the egg in this cycle.
3B. The rise in BT in the middle of the cycle lasts more than 3 days - the egg is either not mature or not viable. Pregnancy in this cycle is doubtful.
4B. P phase less than 12-14 days – failure of phase 2, the egg is not mature or weak, fertilization is in question.
5V. In the P phase, the BT has one or several retractions (decreases below 37.0) - the egg has died.
6B. A decrease in BT before menstruation lasts more than 3 days - the egg was weak, conception is doubtful.
7B. There is no menstruation, and BT remains within phase 2 for MORE than 2 weeks - a likely sign of pregnancy. Pregnancy tests are required.
8B. There is no menstruation, but BT has dropped below 37.0 - pregnancy is very doubtful, most likely we are talking about ovarian dysfunction.
9B. Menstruation is scanty or unusual, and BT remains above 37.0 - pregnancy is possible against the background of the threat of miscarriage. Pregnancy tests are required.
10V. The difference between the average BT value of phases 1 and 2 is less than 0.4* - the egg does not mature.
11B. In the middle of the cycle there is a double rise: BT rises, for example, to 37.1 for 1 day, then decreases to 36.8 for 1-2 days, and then rises to 37.2-37.4 and stays like that until the end - usually a sign of foreign influence during the 1st ascent (illness, diarrhea, etc. - see special notes).
12V. In the middle of the cycle there is a double rise: BT rises, for example, to 37.2 for 2-3 days, then decreases to 36.8 for 1-2 days, and then rises and remains above 37.0, but not as stable as usually, the egg died immediately after maturation.

With a cycle longer or shorter than 28 days, phase 1 is lengthened or shortened (until the temperature rises), and phase 2 in any case should be at least 12-14 days.

A HIGH TEMPERATURE in PHASE 1 (for example, 36.8 in the usual P phase - 37.2-37.4) indicates a INSUFFICIENCY of estrogens, which must be taken (for example, Microfollin 1 tablet per day from the 1st day of the cycle until the temperature rises ).

LOW TEMPERATURE in PHASE 2 (for example, 37.0-37.1; in normal phase 1 - 36.3-36.5) indicates INSUFFICIENCY OF THE CORPUS LUTALUM, which is compensated, for example, by Progesterone (1.0 1% solution in / muscle every other day) or Turinal (1 tablet per day before the onset of menstruation, and in case of pregnancy - up to 10-12 weeks).

HIGH TEMPERATURE in BOTH PHASES (for example, 36.8 and 37.6) while maintaining a difference of at least 0.4* is not a pathology. This condition is called hyperthermic and is a normal individual symptom.

LOW TEMPERATURE in BOTH PHASES (for example, 36.0 and 36.5) while maintaining a difference of at least 0.4* is also a normal individual phenomenon.

BBT SHOULD NOT be measured when taking oral contraceptives: the temperature will be approximately the same throughout the entire cycle, which depends on the concentration of hormones in the tablets, but not on your own hormonal activity.