Value of the basal temperature measurement method

The female body is a relatively stable system, despite the fact that many different physiological processes occur in it every second, causing fluctuations in blood, urine, body temperature, etc. Such changes are insignificant, so small deviations from the average are considered normal, and moderate and large ones are pathology. For example, a body temperature of 36.6-36.8 degrees is considered normal in a normal state, 36.9 is a borderline value, and 37 in most cases indicates a developing pathological process. But this is not always the case, because body temperature is influenced by many factors: stress, physical activity, quality of night rest, the presence of chronic pathologies, pregnancy, etc. Basal temperature during pregnancy is higher than 37 degrees, and this is not considered pathology. On the contrary, such a change in temperature indicators is a joyful event, indicating to some the birth of a new life, and to others - the right moment for conception. [ 1 ]

What is basal temperature?

The word base in Russian is understood as the basis for something, the indicator from which the countdown of changes, time, processes begins. When it comes to something specific, for example, temperature, then the base or basal temperature can be considered the one that most accurately reflects the state of the body at the moment.

This is the temperature in a state of complete rest, when it is not yet noticeably influenced by factors capable of introducing changes. Such factors include:

• physical activity (when a person begins to move actively, metabolic processes accelerate, body temperature rises slightly),
• excited psycho-emotional state (under severe stress and overexcitement, an increase in temperature is observed, in some cases even up to 37.5-38 degrees).
• lack of sleep (with a one-time lack of sleep, weakness and a slight decrease in temperature may be observed, and with chronic lack of sleep, an increase in temperature and chills caused by general fatigue of the body, a decrease in its defenses, resistance to infections), etc.

If you measure your body temperature immediately after waking up, without leaving your bed, it will be several tenths of a degree lower than what we see when a person is actively involved in the hectic rhythm of life. Changes in temperature readings are largely determined by the level of physical activity, the state of the psyche and immunity, the degree of fatigue, so the readings may fluctuate during the day. And this does not allow you to assess the true state of the body.

Basal temperature is the one that is noted when a person wakes up, even before the onset of activity. It is measured in bed, without getting up, taking a thermometer from the bedside table. An important etiological factor is normal rest the day before measuring the temperature (at least 6-7 hours).

Despite equal measurement conditions, even the basal temperature indicators may change in different periods. Thus, the basal temperature during ovulation and pregnancy is somewhat higher than in other periods of a woman's life. But it is important to understand that elevated body temperature indicators may also be the result of inflammatory diseases, the active stage of which is always accompanied by hyperthermia of varying degrees. [ 2 ]

Basal temperature measurement

Since basal temperature most accurately reflects the processes occurring in the body, it is clear that such a feature could not go unnoticed by doctors. The method of measuring it turned out to be useful both for assessing the general condition of the body and for diagnosing pathologies of its various structures and systems (immune, endocrine, reproductive, etc.).

The fact that basal temperature can change even in the absence of symptoms of the disease has interested endocrinologists and gynecologists. The fact is that body temperature can undergo certain changes under the influence of individual hormones. This explains its increase on the eve of ovulation and during conception.

Progesterone has been noted to have a hyperthermic effect. It is this property of the hormone that forms the basis for the method of measuring basal temperature during pregnancy and its planning, developed in the middle of the last century by the English scientist Marshall, although the influence of female sex hormones on body temperature (estrogen lowers it slightly, and progesterone raises it) has been known since the end of the 19th century.

Progesterone is a biologically active substance produced in the body of women and men. But in the latter, it is produced in small quantities and has less activity (its effect and that of estrogens are extinguished by the male hormone testosterone), sufficient to maintain the functional norm of the male body.

Progesterone is of great value to women, because it is thanks to it that pregnancy can be maintained and the demographic situation as a whole can be supported. That is why it is called the pregnancy hormone. But this does not mean that progesterone is produced only in pregnant women.

The female organism is designed in such a way that it is she who is responsible for procreation. The functioning of the female reproductive system is built on this and is subordinated to this task.

Ideally, the menstrual cycle in women can be divided into 2 phases. In the first, one (rarely two or more) follicles mature, in the second, ovulation and post-ovulatory development of the egg. After the follicle matures, a signal is sent to the brain about this, and the pituitary gland releases luteinizing hormone into the blood, facilitating the release of the egg ready for fertilization from the surrounding follicle. Therefore, the first phase is usually called follicular, and the second - luteal.

Once during the menstrual cycle (at the beginning of its second phase), the egg is released from the follicle, forming a corpus luteum in its place (due to a special substance, lutein, which determines the color of the formed gland). The corpus luteum is essentially an organ of internal secretion that exists for a limited time and is designed to maintain pregnancy possible in the postovulatory period.

It is the corpus luteum that is responsible for the synthesis of progesterone in the postovulatory period, regardless of whether conception occurred during this period or not. During the first week after ovulation, progesterone is secreted in significant quantities in both pregnant and non-pregnant women. But after conception, it continues to be secreted in the future, because this is an important condition for maintaining pregnancy. [ 3 ]

Where is basal temperature measured?

Progesterone is a special female hormone that has a specific property of literally "heating up the situation". We are not talking about nervous breakdowns, but about warming up the body's tissues when the hormone enters the vagina and blood. As a biologically active substance, progesterone has a stimulating effect on the thermoregulation center in the brain, which adjusts the temperature in accordance with the requirements for conception and pregnancy.

Some women believe that basal temperature should be measured strictly in the vagina to determine the time of ovulation when planning a pregnancy, because this is where progesterone is synthesized. Perhaps such a measurement is of great value, but not in terms of diagnosing pregnancy, but for identifying gynecological diseases that cause a local increase in the temperature of the genitals. Basal temperature, which changes during ovulation and the onset of pregnancy, is actually the general temperature for the entire body at rest, because our blood circulates throughout the body.

It cannot be said that in the place where the hormone is released, i.e. in the internal female organs, the tissue temperature changes much more strongly, therefore it should be measured only in the vagina. Since progesterone, like other hormones, has an indirect effect, i.e. through the blood, it is the blood that carries this biologically active substance throughout the body, reaching the brain's thermoregulation center. The circulatory system in the human body is the same for all organs. Thus, other parts of the body are also subject to heating, therefore the temperature measured in the oral cavity or rectum, during ovulation and after conception after a short period of time will also be higher.

Another thing is that the sex hormone primarily causes an increase in temperature in the area of its secretion (local), signaling the thermoregulation center that it is here that the necessary conditions need to be created. But later this causes changes in temperature in nearby tissues, and the process spreads further, so fluctuations in basal temperature can be noticed even in the oral cavity.

In other words, an indicator of a joyful event or its maximum possibility is an elevated temperature in the vagina, rectum or mouth, where it is customary to measure basal temperature. The temperature under the arms is not considered so indicative and does not provide accurate information about the state of the reproductive system after the release of the egg from the follicle. After all, we are not talking about a disease, and the temperature changes insignificantly. In addition, the skin is affected by the external environment, so the temperature under the arms is usually lower than that noted on the mucous membranes in places where it is customary to measure it: mouth, rectum, vagina.

The temperature of internal organs and mucous membranes is always higher than that recorded on the surface of the body (skin), although the difference in the norm remains small (only half a degree). And at the same time, it is more stable, because in this case external influences are minimized. It becomes clear why regular measurements of basal temperature in the oral cavity, vagina or rectum are considered more informative.

There is a well-founded opinion that the most appropriate way to measure basal temperature is in the rectum. Why should temperature be measured rectally if all processes associated with the development of the egg and its ovulation occur in the ovaries and vagina of a woman? The authors explain their position by the fact that basal temperature is essentially the temperature of the blood heating of a resting organism, the cyclical changes of which are most noticeable in the rectum, adjacent to the female internal reproductive organs.

Due to the sex hormone progesterone, depending on the level of its secretion by the endocrine glands, the blood supply to the ovaries and uterus, which have common blood vessels, increases. Temperature fluctuations are immediately transmitted to the rectum, which is in direct contact with the walls of the uterus. The intestines heat up when the temperature of the uterus increases, so it is among the first to feel changes in basal temperature.

It would seem that the vagina is also connected to the uterus and ovaries by common arteries, but temperature fluctuations are most noticeable in the depths of this structure when in contact with its walls, while basal temperature is usually measured without inserting the thermometer too far into the vagina. So it turns out that the rectum is the first to know about temperature changes in the reproductive organs, located beyond the reach of the thermometer, and to react to them.

And yet, regardless of the choice of location for measuring temperature readings, a woman planning a pregnancy will have to adhere to certain requirements:

• Temperature should be measured regularly throughout the menstrual cycle. This is the only way to notice small changes during ovulation and conception. If measurements are taken occasionally, then a convenient moment for sexual intercourse with the greatest chance of conceiving a new life can simply be missed. The fact is that the highest probability of becoming a mother is the day of ovulation. Ovulation occurs in the middle of the menstrual cycle, and this middle is calculated based on the number of days in the cycle, and can shift in different women, especially in those whose cycle is not particularly regular. Basal temperature, or rather its measurement, will help determine the day of ovulation most accurately.

But it is important to understand that conception can also occur on other days, close to the day of ovulation, if a woman has not one, but two eggs (in both ovaries) that remain viable for 1-2 days and are most favorable to sperm during the first 12 hours. The eggs can mature simultaneously or with an interval of up to 7 days, i.e. not one, but two ovulations will occur.

One of the reasons for a later (less often earlier) period of conception can also be considered the viability of spermatozoa (inside the female body they can maintain their activity for a week, when the probability of getting pregnant remains even in the absence of an act of love during these days). This indicates errors that are possible if you use not the temperature, but the calendar method of determining the best day for conception and pregnancy diagnosis.

• When planning a pregnancy, it is better to back up the measurement of basal temperature with the corresponding records. Using the results of daily measurements, you can easily create a chart, according to which women with a regular menstrual cycle can calculate the optimal days for conception in the future, even without measuring temperature. Such a chart will also be useful for diagnosing the processes occurring in a woman's body: if the basal temperature after ovulation does not gradually decrease for 2 or more weeks, then it is time to visit a women's consultation. It is quite possible that pregnancy has occurred.

The corpus luteum, which forms after the egg leaves the follicle, functions for several months after conception (it is especially active up to 6-7 weeks of pregnancy, but with the appearance of the placenta it begins to lose its role). All this time it secretes progesterone (the maximum activity of the corpus luteum is noted on the 6-7 day after ovulation) and thus maintains not only pregnancy, but also an elevated body temperature in the expectant mother.

If conception does not occur, the activity of the corpus luteum decreases within a week, and progesterone production quickly fades (usually after day 21 of the cycle), which is accompanied by a decrease in temperature to normal levels in non-pregnant women.

• An important condition for the adequacy and value of measurements is not only their regularity, but also their consistency: the same thermometer, approximately the same time of measurements (ideally in the morning), the same place (oral cavity, vagina or rectum), because the temperature varies in different parts of the body.
• You need to measure your basal temperature starting from the 1st day of your cycle (the first day of your period), even before you get out of bed, so it is advisable to have a thermometer at hand after waking up in the morning. You should postpone going to the toilet, performing hygiene procedures, and eating until later, because any activity of the body affects the temperature readings (blood circulates more actively and heat exchange occurs between the body's tissues).

This should be done daily, trying to avoid significant time differences (plus or minus half an hour). If for some reason a woman overslept the time of the morning measurement, it should be noted in the chart or diary, because this result will not be accurate enough for dynamic analysis. It is believed that during 1 hour of morning sleep, the basal temperature can rise by 0.1 degrees, i.e. having slept an extra couple of hours, you can get a basal temperature indicator 0.2 degrees higher.

• Only those results are indicative when the body has previously received normal rest for at least 6 hours. It is desirable that in the last 3 hours of sleep the rest is not interrupted by trips to the kitchen or toilet.

If a woman has to work at night, the temperature should be measured after the body has rested for 3-4 hours (there is no point in measuring the temperature early in the morning). But it should be said right away that shift work schedules negatively affect the hormonal balance and the ability to conceive a child.

In adolescence and youth, night shifts and lack of normal night sleep can lead to disruption of the development of the pelvis and problems with conception in the future. The growth of the pelvic bones, and therefore the normal development of the pelvis and its organs, is promoted by the pituitary hormone somatotropin - a growth hormone produced at night.

During puberty, the production of this hormone is most active, and subsequently decreases significantly. Underdevelopment of the pelvis during puberty is almost impossible to compensate for in the future, and as a result, problems with conception, bearing and birth of a child.

• For the accuracy of the measurement, the depth of insertion of the thermometer and the time of temperature measurement are important. The device should be inserted into the oral cavity, rectum and vagina at least 4 cm, but immersing it "with the head" also does not make sense. The measurement time should not be less than 5-7 minutes, when the device readings stabilize and will no longer change.
• During menstruation, it is uncomfortable to measure basal temperature in the vagina, but only those results that correspond to a specific measurement location throughout the cycle are valuable. That is, if you measure temperature in the mouth during menstruation and in the vagina after it, there is a certain risk of error.

Based on these considerations, it can be assumed that when planning a pregnancy, it is better to measure basal temperature in the rectum, which is located in close proximity to the woman’s internal reproductive organs (if there are contraindications to such measurements or other subjective reasons, the temperature can be measured by holding the thermometer in the mouth).

During pregnancy and the absence of menstruation, it is best to measure basal temperature in the vagina. This is a fairly effective and safe method of monitoring the ongoing pregnancy, which can signal the risk of its failure, local inflammatory processes, usually associated with a bacterial infection (the temperature in the mouth and rectum may remain unchanged), or the absence of cause for alarm. Such measurements will not cause harm to the fetus, because the thermometer does not need to be inserted deeply (the main thing is to ensure the sterility of the measuring device so as not to introduce an infection into the genital tract), but they will allow the mother to promptly suspect violations and prevent them by contacting a doctor in time. [ 4 ]

Who needs to measure basal temperature and why?

Regular measurement of body temperature at rest gives a clear picture of both the general health of a person and its individual organs and systems, and in particular the reproductive system. From a gynecological point of view, it is of great value for monitoring the condition and functioning of the ovaries. It is the work of the ovaries that primarily determines a woman's ability to continue the family line, because follicles with maturing eggs are formed in them - female reproductive cells, which, in agreement with one of the spermatozoa (male reproductive cell), give rise to a new organism.

Often, women whose health does not seem to cause concern, but nevertheless they are unable to conceive a child (conception does not occur at all or low levels of female sex hormones cause miscarriages in the early stages, turn to a gynecologist). Usually, after 1-2 years of unsuccessful attempts, such women seek help from a doctor who cannot make a diagnosis and prescribe treatment without knowing the cause of the disorders. Often, such reasons are hormonal in nature, which will be indicated by the results of measuring the basal temperature.

Consulting a doctor and using the temperature method of diagnosing infertility will be useful in cases of long-term unsuccessful attempts to conceive a child (it helps to identify which man or woman is unable to conceive, as well as to determine the reason for this in women), regular miscarriages, and suspected hormonal imbalances in women.

In these situations, the doctor himself can offer such a simple and effective diagnostic method, which also helps to identify diseases of the genital (when measuring the temperature in the vagina, inflammatory processes are easily detected) and endocrine systems (given that the gonads themselves are stimulated by the pituitary gland and adrenal glands with the participation of the thyroid gland). In the latter case, a consultation is necessary not only with a gynecologist, but also with an endocrinologist, because a failure can occur in any link of the endocrine chain, which will affect the synthesis of sex hormones, and in particular progesterone.

It is clear that professional diagnostics of disorders is not limited to measuring basal temperature, drawing up a chart and interpreting it. The doctor has no right to make a final diagnosis without laboratory tests and a full examination of the woman, including a hormone test. After all, temperature fluctuations are not always caused by ovulation and conception, it can also be a symptom of a disease that has not yet declared itself.

Despite the fact that the method of measuring basal temperature is related to methods of medical diagnostics, its use does not require special equipment and supervision by a doctor. Any woman can measure temperature indicators and make a simple graph by connecting points corresponding to digital temperature indicators. Gynecologists themselves often recommend women to use the method when planning a pregnancy to determine the optimal day of the female sexual cycle for conception.

But even if having a child is not the most important goal in this period, basal temperature will help to identify some deviations in the functioning of the ovaries, which may become an obstacle to pregnancy in the future. For example, non-maturation of the egg or lack of ovulation with normal development of the egg, when it does not leave the ovary and the corpus luteum, which produces progesterone, is not formed. In such conditions, it is impossible to conceive a child and the woman should consult a doctor in advance to identify the reasons for the non-maturation of the egg and appropriate treatment.

If everything is normal and ovulation occurs, measurements will help:

• avoid unwanted pregnancy, as they will determine the days when it is worth paying special attention to contraception or abstaining from intercourse,
• will provide certain information about the functioning of the endocrine system and the sex glands in particular,
• will help to identify hidden pathologies,
• will help you determine the time of the next menstruation,
• will make it possible to determine the possible causes of delayed menstruation, the appearance of unusual discharge (these occur during implantation of the egg on the 3-7th day after conception, and not only with gynecological diseases).

Future mothers who strictly monitor their health and pregnancy do not stop taking measurements even after conception. It is especially important to monitor changes in basal temperature during the first four weeks of pregnancy, when the risk of miscarriage is especially high. The restructuring of the mother's body makes it more susceptible to any negative factors that affect it from outside or inside. Fluctuations in basal temperature in one direction or another from the norm may indicate an increased risk of spontaneous abortion.

Thus, in order to start measuring basal temperature when planning a pregnancy or for preventive purposes, it is not at all necessary to go to a gynecologist for such an appointment. It is much more important to consult a doctor if the chart shows deviations from the norm, which may be evidence of both physiological (pregnancy) and pathological processes. [ 5 ]

The pleasant and terrible secrets of basal temperature

When a woman takes basal temperature measurements for the sake of interest and contraception, she is not concerned about the absence of pregnancy for a long time and other issues related to procreation, the results of the measurements are unlikely to cause strong emotions in her. When planning a pregnancy, monitoring it or diagnosing infertility, women are more scrupulous about the method and react sharply to any deviations from the generally accepted norm.

If the basal temperature is measured for the purpose of conceiving and keeping a child during pregnancy, then the very fact that it fluctuates can cause alarm. Sometimes it is groundless, because we have already said that normally the temperature during the menstrual cycle should fluctuate, especially at the border of the phases after ovulation (a large jump in temperature within 0.4 degrees, although usually the difference does not exceed 0.1-0.2 degrees). It is worse if the graph remains monotonous throughout all days of the cycle and does not experience noticeable fluctuations. Although preovulatory temperature drop is not observed on the graph of about 20% of healthy women, it is clear that the jump in temperature after ovulation will not be so noticeable.

But in some cases, jumps in basal temperature within one of the phases may be evidence of certain pathologies. For example, knowing that in the first phase of the cycle the temperature is usually below 37 degrees, its jump above this indicator for 2-3 days or a long stay near the normal limit may indicate inflammation of the appendages.

In the second phase of the cycle, the temperature indicators are normally above 37.1 degrees. In the first 3 days after ovulation, they grow especially quickly, then the rate of temperature increase decreases, on the 6-7th day at conception, a decrease in temperature by 0.2-0.3 degrees is observed (implantation depression), after which the temperature again gradually increases while the corpus luteum is active, i.e. almost until the end of the second phase. If 3 days after ovulation the temperature continues to rise sharply, one can suspect an inflammatory process in the genitals, egg pathology, estrogen deficiency, the effect of which on temperature is opposite to progesterone.

Basal temperature after ovulation during pregnancy should remain above 37.1 degrees at least during the first month of pregnancy, but usually some deviation from the norm towards an increase is noted in the second and third months of pregnancy. Temperature within 37.1 -37.3 for 14 or more days after ovulation in the absence of another menstruation most likely indicates a joyful event in the life of a woman and her family. A two-week pregnancy is already well determined by tests that will help to make sure of the truth of the desired event.

But even if your period has arrived, it does not mean that pregnancy should be ruled out (some women experience their period for several months during pregnancy). A shift in the onset of menstruation, unusual discharge, or a decrease in the duration of menstrual bleeding may indicate conception, but in such cases, pregnancy is usually considered problematic due to the threat of miscarriage already in the early stages.

Basal temperature of 36.9 – 37 degrees in the first phase of the cycle when planning pregnancy indicates a lack of estrogens in the body. Even if the egg can mature in such conditions and ovulate, it will most likely be weak. But usually, with a lack of female hormones, eggs do not mature and there is no sharp increase in temperature in the second phase of the cycle.

The same temperature in the second phase of the cycle indicates a borderline condition and confirms progesterone deficiency (and sometimes a deficiency of sex hormones in general) regardless of whether conception has occurred or not. In this case, the introduction of hormones from the outside, stimulation of hormonal activity is required, otherwise the chances of conception and normal pregnancy are low.

A basal temperature of 36 degrees when planning a pregnancy can be in the first phase of the menstrual cycle, especially against the background of a general weakening of the body. In the second phase of the cycle, such a low temperature is more likely to be nonsense and is possible only with acute progesterone deficiency. Most likely, we are talking about the absence of ovulation, without which conception is impossible.

A significant drop in basal temperature in a pregnant woman can be observed in case of a frozen pregnancy, which requires immediate surgical intervention. The cause of such a miscarriage can be hormonal disorders, for example, progesterone deficiency (as evidenced by the low temperature level), its imbalance with estrogens, dysfunction of not only the ovaries, but also other endocrine organs (especially the thyroid gland, pituitary gland and adrenal glands) responsible for maintaining hormonal levels. Usually, the temperature does not fall below 36.5 degrees, but these indicators are strictly individual. Any decrease in basal temperature during pregnancy below 37 degrees should be regarded as an alarming factor. At 36.8, you can no longer postpone a visit to the doctor.

In case of ectopic pregnancy, the basal temperature is usually within the normal range, if there are no hormonal disorders. Temperature changes are caused by the production of progesterone, which is released after ovulation - a necessary condition for conception. If we are talking about pregnancy, regardless of its location, ovulation occurred in any case, which means that a large amount of progesterone was released into the blood. Thus, measuring the basal temperature in case of ectopic pregnancy has no diagnostic value.

Now let's talk about high temperature readings. 37.1 - 37.3 degrees are normal readings for the second phase of the cycle. Borderline conditions are 37.4 -37.6 degrees. These are generally accepted norms that may differ depending on the initial temperature in the first phase of the cycle.

If in the second phase of the cycle the temperature exceeds 37.6 degrees, it is highly likely that there is an inflammatory process, although similar results may also occur with estrogen deficiency. A basal temperature of 38 degrees during pregnancy (or in the second phase of the cycle without conception) is observed with infectious and inflammatory processes in the internal genital organs of a woman.

Thus, an increase or decrease in basal temperature during pregnancy can have various causes. Excessive growth of temperature indicators is usually associated with inflammatory processes in the reproductive system, and in the first phase of the cycle it can also be evidence of estrogen deficiency. A decrease in temperature indicators is considered more unfavorable in terms of conception and pregnancy, especially in the second phase of the cycle, which is associated with progesterone deficiency, fetal fading, and an increased risk of spontaneous miscarriage in the early stages of pregnancy. [ 6 ]

Basal temperature during IVF pregnancy

Women are not always able to conceive a child naturally. For example, in case of anatomical defects and obstruction of the fallopian tubes, in vitro fertilization (IVF) is often the only way to become the mother of your child.

This method is attractive because the future child receives hereditary information from both parents. The meeting of the mother's egg and the father's sperm simply occurs outside the mother's body. The egg is returned to the mother's body (implanted in the uterus) after conception, i.e. 2-5 days after it. After conception, it is considered an embryo.

The problem is that mature follicles are extracted before they rupture, i.e. before the formation of the corpus luteum, which produces progesterone. By placing the embryo in the uterus, it is impossible to resolve the issue of maintaining pregnancy without introducing a hormone from outside that supports it (progesterone). After all, until the moment of placenta formation, there will be no one to produce progesterone in sufficient quantities, and the hormones of the adrenal glands (analogues of hormones secreted by the sex glands) are not active enough to maintain pregnancy.

To monitor the course of IVF pregnancy using the basal temperature chart, you need to start measuring it 2-3 months before implantation, excluding periods when hormonal stimulation of follicle maturation is performed before their extraction. This will help doctors determine the normal temperature and hormonal background of a woman, which will then make it possible to calculate the necessary dosage of progesterone.

During natural conception, the temperature rises to 37.3 degrees in the first days after ovulation. During IVF, the temperature can reach 37.5 degrees in the first days after implantation (the body's reaction to the introduction of a foreign body is added to the action of progesterone). Ideally, progesterone restrains the aggressive immune response and the temperature subsequently remains within 37.2-37.4 degrees, as with natural conception. When the embryo is implanted in the uterine wall, a small short-term jump in temperature is possible, but then everything returns to normal.

If the temperature continues to rise and then drops and becomes below 37 degrees, this is most likely evidence of rejection of the embryo as a result of increased activity of the immune system. Although there may be other reasons:

• the temperature sometimes rises or jumps in both directions during an ectopic pregnancy,
• local increase in temperature also causes local inflammatory processes,
• hyperthermia is characteristic of common infectious diseases,
• Infectious complications also cannot be ruled out (they are possible at the time of egg collection or its implantation in the uterus).

Any changes in basal temperature during pregnancy after IVF should be closely monitored and analyzed during the first trimester of pregnancy. After placentation of the embryo, the placenta takes responsibility for maintaining the pregnancy and monitoring the basal temperature no longer makes sense, although pregnancy monitoring by specialists should remain regular.

A little about the accuracy and appropriateness of the method

Many specialists are skeptical about the method of measuring basal temperature, arguing that its graph itself is not a reliable diagnostic criterion. Thermometer readings can be affected by various internal and external factors that devalue the graphical method. Such factors include: somatic diseases that can cause an increase in temperature, night and especially morning sexual intercourse, taking medications and using contraceptives (even one-time), which contribute to changes in hormonal levels, stress factors that cause irregular absence of ovulation, etc.

A basal temperature chart for pregnancy planning and early pregnancy will be more informative if the drawing is accompanied by notes on the woman's well-being and situations that can correct the actual indicators. If in the interval between consecutive temperature measurements the woman had no sleep disturbances, unusual discharge, pain not associated with menstruation, nervous shocks, sexual intercourse, stool disorders, no notes need to be made. But it is necessary to mention the medications taken, especially if we are talking about steroids, hormone-containing drugs, sexual function stimulants.

By the way, it is worth giving up hormonal contraceptives during the menstrual cycle, when the basal temperature is measured, altogether. After all, in this case, the thermometer will show temperature changes corresponding to the effect of contraceptives, i.e. there is an external influence that changes the course of processes inside the woman's body.

In a separate column, it is worth noting such events as bowel disorders (constipation and diarrhea), painful sensations (regardless of their location), the presence of symptoms of the disease, days of menstruation and the nature of their course, alcohol consumption, sexual intercourse, sleep disorders (frequent awakenings, insufficient duration, fatigue after waking up, taking sleeping pills).

Special attention should be paid to discharge during the menstrual cycle, which in adult women normally occurs not only during menstruation. Information about the nature of discharge on different days of the cycle will be very valuable for a specialist. During ovulation, they usually become more abundant, transparent, mucus-like, sometimes with streaks of blood. The onset of ovulation may also be indicated by "filled" and slightly painful breasts, increased sexual desire, unusual bloating and slight aching pain in the lower abdomen, sometimes flatulence. All this should also be mentioned in your notes.

Basal temperature is an important indicator of the state of the female reproductive system when planning and monitoring pregnancy. But it cannot be used alone when making a diagnosis. A normal two-phase cycle usually means a two-phase change in temperature. But statistics show that a fifth of healthy women with a two-phase menstrual cycle are diagnosed with a multi-phase change in basal temperature, i.e. noticeable temperature fluctuations during one phase of the cycle, and not only when they change. Ultrasound and laboratory tests do not confirm any pathologies or obstacles to conception, although the graph looks unusual.

Another point. In the case of luteinization syndrome of an unovulated follicle, ovulation does not occur, but at the same time, a two-phase change in temperature is again observed. However, in this case, the rate of temperature increase in the second phase of the cycle is unusually low. It is this fact that is recognized by doctors as a diagnostic criterion.

Many factors influence changes in basal temperature. Any active movement, such as getting up to take a thermometer, can reduce the value of the result, not to mention sexual activity, taking medications, lack of sleep, stress, drinking alcohol, etc., which are considered ordinary everyday situations in our lives. In addition, to obtain a reliable result for various disorders, it is necessary to use the method of measuring and comparing basal temperature over not one, but several menstrual cycles. And in any case, this information should be supported by the results of ultrasound and hormone tests.

Basal temperature during pregnancy and at the stage of its planning cannot be considered the main diagnostic criterion for infertility, miscarriage and many other disorders that prevent a woman from becoming a mother. The results of measurements only help a woman and a doctor to assume possible hormonal causes of reproductive system malfunctions. However, for determining the day of ovulation, dangerous periods when special attention should be paid to contraception, daily monitoring of the course of pregnancy in the early stages for timely seeking help if necessary (a kind of insurance), this method is considered a worthy alternative.