What does the basal temperature chart during pregnancy tell you? When to visit a doctor. Endometritis on the example of a graph

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

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

The essence of the method

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

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

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

What you can find out

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

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

When is it useful to use the method

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

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

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

How to make your research accurate

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

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

How to do it correctly

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

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

Ideally basal temperature readings

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

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

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

Table - Important values in the BT chart and normal options

Measurement period	What does it indicate?	What should be normal
From 1 to 14 days of the cycle	- Estrogen levels	- Immediately after menstruation, the temperature drops to 36.6-36.2℃
A day or two before ovulation	- Peaks in the release of ovulation hormones	- Readings begin to rise to 36.6-36.7℃
On the eve of ovulation (day 14)	- Rupture of the follicle with a sharp increase in luteinizing hormone	- Basal temperature during ovulation can “fall” by 0.1-0.4℃
Immediately after the release of the egg (ovulation)	- Normal secretion of progesterone by the corpus luteum	- Increased basal temperature all the time before menstruation (37-37.4℃)
From 16 to 28 days of the cycle	- High progesterone levels mid-cycle	- Starting from 12-14 days almost before the start of menstruation, the rectal temperature is high (above 37℃)
On the eve of menstruation	- Decrease in progesterone levels at the end of the cycle	- Temperature reduction to 36.8-36.7℃

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

Possible deviations

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

Doctors and women have to deal with the following deviations.

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

What changes are recorded during normal and pathological pregnancy?

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

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

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

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

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

If you do not know how to properly organize pregnancy planning, basal temperature will help you determine the onset of ovulation. Knowledge of some physiological processes of the female body allows you to find out on what days you can conceive a baby. In addition, if failures in these processes are detected, the cause of many health problems can be determined.

Basal temperature is the lowest indicator of body temperature after a night's sleep, which can be used to determine how warm the human body is due to the work of all organs and systems without heating due to muscles.

Basal temperature can be measured with either a mercury or an electronic thermometer.

You can use either a regular mercury thermometer or an electronic thermometer. Temperature can be measured rectally or vaginally. To ensure the most accurate readings, please observe the following: recommendations:

Before measurement, you need to sleep at least five to six hours at night without interruption,
preferably sleep under the same blanket and in the same clothes (pajamas, nightie),
take the measurement at the same time every day before you get out of bed,
prepare a thermometer and a clock in advance and place them close to you, it is better to do this in the evening,
measurement time takes from five to eight minutes,
while drawing up the schedule, exclude alcoholic beverages, oral contraceptives,
a prerequisite for measurement is the absence of inflammatory processes in the genitourinary system,
Record your thermometer readings in your diary every day.

How to make a schedule?

You can simply record the readings in a diary, or you can immediately create a schedule. To do this, it is convenient to use a regular squared notebook. Draw a graph, take one cell as a unit: vertically there will be temperature indicators (1 cell is 0.1 degrees), and horizontally there will be days (1 cell = 1 day).

Be sure to note any violations of the regime: drinking alcohol, stress, disruption of sleep patterns. To obtain the most accurate information, it is necessary to keep a diary for at least 3 cycles in a row. The schedule must be shown to the gynecologist, who can use it to determine the onset of your ovulation. In addition, this information will help the specialist understand how your reproductive system works and what condition it is in.

Basal temperature readings can help you if:

you are planning a pregnancy and want to determine favorable days for fertilization,
there is a suspicion of infertility after regularly trying to conceive a baby for about a year,
your menstrual cycle is disrupted and you need to determine your hormonal status.

We determine ovulation by basal temperature indicators

The menstrual cycle is divided into two phases: the first begins with menstruation, during which the egg matures. Then ovulation occurs. Conception can occur within 1-2 days from the beginning of the ovulation process. Then the egg dies.

Immediately after the death of the egg, the 2nd phase of the cycle begins, during which progesterone is released in the body. This hormone prepares the body to accept the embryo. If fertilization does not occur, the cycle begins again.

Important: indicators in the first phase of the cycle are lower than at the beginning of the second. After ovulation, the temperature rises provided that the body produces enough progesterone.

The duration of the second phase is about 13-14 days; before the start of menstruation, the temperature drops sharply by 0.3 - 0.4 degrees. If conception has occurred, the indicators increase.

Conception can occur within 1-2 days during ovulation.

Normal: indicators in the second phase are increased by 0.5 g. The elevated temperature usually lasts until the start of menstruation, then a decrease of 0.4 - 0.6 degrees is observed. This is a signal of ovulation.

When progesterone production begins after ovulation and the temperature rises by 0.3 - 0.6 degrees, the time of ovulation can be determined.

Important: Indicators may depend on many external and internal factors: stress, hypothermia, sexual intercourse.

How do you know that conception has occurred?

If you keep a schedule regularly, you can use it to determine the onset of conception: at the end of the second phase there is no drop in temperature, and if menstruation is delayed, the temperature usually stays at 37 degrees (and higher). If the pregnancy proceeds without complications, the readings will be above 37 degrees.

A decrease in temperature is often a signal of a threat of miscarriage or a non-developing ovum. In some cases, it is necessary to visit a gynecologist:

Several cycles in a row, judging by the graph, you are not ovulating.
Throughout the entire cycle, indicators are increased or decreased.
The cycle is shorter than 21 or longer than 35 days.
With regular sexual activity and ovulation, pregnancy does not occur.
In the second phase, after 18 days, the temperature is elevated and the pregnancy test is negative.

Every woman should monitor her health. To do this, you need to visit a gynecologist once every six months, if there are no deviations in your health. Many diseases in the initial stages of development can be asymptomatic.

To determine possible malfunctions in the functioning of the systems of the female body, it is recommended to draw a graph of basal temperature. Any physiological and pathological changes can be revealed by the measurements taken.

The concept of basal temperature

Basal temperature (BT) is the temperature of the body's blood during sleep. It is measured in the rectum. It can also be detected in the vagina or mouth. But cyclic fluctuations can be shown by rectal temperature. This occurs due to the peculiarities of the blood supply to the ovaries. Other measurement methods are also capable of capturing cyclical fluctuations, but only when they are pronounced.

Only rectal temperature can determine subtle changes in heat exchange in the ovarian vein. You need to understand two things:

If there is no opportunity (or desire) to regularly measure BT rectally, it is better not to use this method at all.
The basal (rectal) temperature chart is not used to make a diagnosis or prescribe treatment.

Any deviations from the standards should be discussed with a gynecologist.

Purpose of the method

To correctly understand what basal temperature is, you need to understand why this method is useful. Its main advantage is the ability to clearly define the processes of each phase of the cycle and identify possible deviations in the functioning of the body.

The norm established by medical specialists is an ideal. Each organism has its own characteristics. To take them into account and be able to draw a correct conclusion, observations are carried out for at least 3 months. It is recommended to plot your basal temperature for several reasons:

The method allows you to determine the moment of ovulation and highlight days favorable for conception.
Rectal temperature changes in a certain way during pregnancy. This suggests that the woman is pregnant in the early stages.
Measuring BT helps determine the causes of infertility.
Makes it possible to identify the presence of pathologies in the body.
With its help you can check the quality of the endocrine system.

However, it is possible to achieve sufficient information content of the method only if the rules for constructing a BT graph are followed. In order to adequately draw it, it is necessary to clearly fulfill a number of requirements.

Data Collection Rules

Rectal temperature is measured according to certain rules. The correctness of the result depends on this. The method has a number of requirements:

Data collection is carried out at one time with a maximum deviation of 30 minutes.
The thermometer should be prepared in advance so that you do not have to get out of bed. You should move as little as possible, otherwise the temperature will increase by 0.1–0.2 thermometer divisions. This will affect the decoding of the result.
Measurements are taken daily, including the menstrual phase.
Continuous sleep before the next BT measurement should be at least 4 hours.
Illness, stress, increased loads affect the result. Therefore, if there are such facts, notes should be made in the notes.
You must use the same thermometer. A mercury device is preferable, although an electronic version can also be used.

All results are immediately recorded in the log. Based on them, a schedule is built.

Plotting a graph

To make data collection results easier to interpret, they are usually presented graphically. Deciphering such information should be done by a qualified specialist. A woman can independently construct such graphs in several cycles.

It is possible to complete the drawing manually or use an online program. This will make the diagnostic process easier for the gynecologist.

Charting technology

All measurements recorded in the log must be presented graphically. If it is preferable to make the drawing manually, you should take a piece of paper in a cell and draw an x-axis (X), on which each cell corresponds to a day of the menstrual cycle. Accordingly, the ordinate (Y) axis is assigned to degrees. One cell is equal to 0.1 thermometer division.

The entire cycle must fit on one sheet. You should not record readings for several periods on one chart. This leads to errors and difficulties during decoding.

A basal temperature of 37.0 is an important cutoff in this study. Therefore, at this level a line is drawn parallel to the abscissa axis. All measurement results are plotted on a graph in the form of points. They are then connected in series. The norm is determined only after several months of research.

There are a large number of programs on the Internet that simplify the process of plotting. The research results are entered online into the appropriate cells. The program will build a smooth graph. This approach is as informative as drawing by hand.

Notes on the chart

Basal temperature in early pregnancy and during the cycle without conception is different. However, to see this difference, you need to do the research correctly.

Any little thing that a woman might not have paid attention to before can affect the result. Therefore, it is necessary to record not only the thermometer readings, but also a number of additional data. Without them, basal temperature in early pregnancy can easily be perceived as an abnormality or go unnoticed altogether. Factors that can influence BT include a number of conditions:

Diseases with increased general body temperature.
Intimacy in the evening or at night.
Drinking alcohol.
Short period of sleep.
Unusual measurement time.
Taking sleeping pills.

A graph of basal temperature can be drawn by omitting single unreliable data. This should be noted in the notes. The type of discharge from the genital tract is also indicated here daily.

With the onset of pregnancy, gynecological diseases, and hormonal imbalances, their nature changes.

Normal chart type

The individual characteristics of a woman’s body affect the appearance of the graph. Each representative of the fair sex has her own norm. However, there are general principles that allow you to understand what your basal temperature should be.

The following statements are considered examples of normal graphs. They are considered in the context of the cycle with conception and in its absence.

Normal schedule for a period without conception

To answer the question of what basal temperature a non-pregnant girl should have, we need to consider the features of the menstrual cycle. It consists of follicular and luteal phases.

During the maturation of the egg, estrogen is produced, and after its release into the fallopian tube, the amount of progesterone in the blood serum increases. From the first day of the cycle (the beginning of menstruation), BT drops to the limit of 36.3–36.5 degrees. It remains this way in the follicular phase.

2 weeks before the expected date of the next menstruation, a sharp increase in indicators is observed. A basal temperature of 37.0–37.2 indicates that ovulation has occurred.

Moreover, the difference between the second and first phases should be 0.4–0.5 degrees.

This process is influenced by progesterone, which is intensively produced in the luteal phase. It prepares the body for a possible pregnancy. If it has not occurred, then 24–48 hours before menstruation, measurements will show a gradual decrease to 36.8–37.0 degrees.

Normal during pregnancy

Many couples are interested in what basal temperature during pregnancy is considered normal. This is a really important indicator. When pregnancy occurs, progesterone is actively produced. He is responsible for the processes of the correct course of this state.

Rectal temperature during pregnancy in the first obstetric weeks is completely identical to the chart without conception having occurred. The normal BBT after ovulation in this case is recognized in the range of 37.0–37.2 degrees.

One of the first signs of successful conception is the absence of a decrease in this indicator before the day of the expected menstruation.

If there is a delay at a high level of the measured indicator, you should consult a doctor. After undergoing an appropriate examination, the gynecologist will be able to accurately diagnose the cause of this condition.

The graph will also clearly show the implantation temperature drop over several days. This is due to the attachment of the fertilized egg in the uterine cavity and the hormonal changes that occur. All these factors lead to a temporary recess of the curve on the graph.

Basal temperature during pregnancy remains high, which indicates a sufficient amount of progesterone.

Deviations from the standard schedule

The normal basal temperature indicators are determined after consultation with a doctor. Only a medical specialist, based on the examinations performed, will help to adequately understand the signals of the female body. Deviations in the course of various processes can be caused by various factors.

Hormonal disbalance

Improper production of progesterone and estrogen is shown in the drawing as the absence of a sharp jump in temperature in the middle of the cycle. If ovulation has not occurred this month, the indicator curve will not have any sharp rises or falls. Luteal phase deficiency is characterized by a duration of less than 12 days.

A basal temperature during pregnancy of 36.6–36.9 also indicates insufficient progesterone production. This threatens spontaneous abortion. You need to go to the hospital immediately.

But estrogen deficiency is determined by a high level of temperatures in the follicular phase. If this indicator is above 36.7 before the middle of the cycle, you should consult a medical specialist.

Inflammatory processes

In addition to the hormonal imbalances listed above, the graph may show the presence of inflammatory processes. This situation is reflected in the form of fluctuations in the curve and an increase in temperature.

With inflammation of the appendages, such a picture will not even allow you to determine the moment of ovulation. Sharp declines and rises indicate deviations of an inflammatory nature.

An increase in rectal temperature before the next menstruation allows one to suspect the development of endometritis. The graph will show a slight decrease in the curve in the last days of the cycle, and then its increase to 37.0.

If your period has not started, you may be pregnant. But in its absence, such a condition indicates a possible pathology.

Today, the method of determining basal temperature is recognized as a fairly reliable method for identifying various processes in the body.

By following all the rules for collecting data, a woman can get a true result with a high degree of probability. This will help her gynecologist quickly draw conclusions about the state of her health and, if necessary, take timely measures to prevent the development of pathology.

(BT) is the body temperature at rest after resting for at least 3-6 hours (mainly after a night's sleep). It is after rest that the body has the lowest temperature. Its measurement has found practical application in obstetrics and gynecology, since the value of basal temperature can be used to judge the presence and time of ovulation, duration and usefulness (follicular, ovulation, luteal).

general information

For convenience, the basal temperature is marked on the chart for at least three menstrual cycles. A basal temperature chart can show the following:

whether ovulation occurs;
on what day does ovulation occur (helps to plan a child or, conversely, to protect against pregnancy);
does the menstrual cycle have two phases;
Is the duration of the second phase sufficient?
if menstruation is delayed, it allows you to judge whether pregnancy has occurred;
Is the second phase hormone progesterone being produced sufficiently?

information Measuring morning rectal temperature allows you to determine the presence of ovulation, as well as the severity and duration of the second phase of the cycle. During a normal menstrual cycle, basal temperature rises by 0.4-0.8 ° C during the luteal phase.

A persistent two-phase graph of basal temperature over 3 menstrual cycles indicates a normal, stable temperature.

Measurement Rules

Basal temperature is measured in the rectum, vagina, and oral cavity, but the first method is the most common.
A mercury or electronic thermometer is used for measurement. It is important to use the same thermometer throughout the entire menstrual cycle.
The thermometer is inserted 3-5 cm into the rectum, wait for 5 minutes if using a mercury thermometer, or until the signal when measuring electronically.
Basal temperature is measured after at least three hours of rest (sleep), without getting out of bed, before any physical activity. To do this, it is recommended to leave the thermometer close to the bed so that you can get it out without any effort.
Basal temperature must be measured at the same time every day.
Morning rectal temperature may change after sexual intercourse the day before, against the background of any infectious disease, stress, alcohol intake, lack of sleep, loose stools, etc. All these conditions must be noted on the chart.
For a clear and accurate picture, BT should be measured for at least 3 months, since even a healthy woman may not ovulate up to 2-3 times within a year. Lack of ovulation for 3 menstrual cycles in a row is a reason to consult a gynecologist.

Basal temperature phases

Basal temperature depends on the functioning of the ovaries, and more precisely on the level of sex hormones (estrogen and progesterone). can be divided into three phases:

follicular;
ovulation phase;
luteal

First ( follicular) phase in one of the ovaries, under the influence of follicle-stimulating hormone, the maturation of follicles (a cell that contains an egg surrounded by liquid) occurs. These cells secrete the hormone estrogen.

information In each menstrual cycle, 5-8 follicles begin to grow simultaneously, by the 7th day of the cycle the largest of them becomes dominant (main), the rest die. By the middle of the cycle, the dominant follicle reaches its maximum size (20-25 mm).

Under the influence of follicle-stimulating and luteinizing hormone, the dominant follicle bursts, the egg leaves the ovary into the abdominal cavity and then enters the fallopian tube. This process is called ovulation.

In place of the burst follicle, a corpus luteum is formed (has a yellow color on a section of the ovary). Its cells, under the influence of luteinizing hormone, begin to produce progesterone. The bloom of the corpus luteum is observed by days 19-21 of the menstrual cycle. If pregnancy has occurred, it continues to synthesize progesterone. The corpus luteum functions until the 16th week of pregnancy. If the egg is not fertilized, it regresses and, as a result, progesterone levels decrease. The phase from ovulation to the next menstruation is called luteal.

Schedule

All the described changes are reflected in basal temperature chart.

During the follicular phase, under the influence of the hormone estrogen, the basal temperature is relatively low (36.4-36.8 ° C).
The maximum level of estrogen is released during the preovulatory period, so a decrease in temperature is observed 1-2 days before ovulation. After ovulation, the cells of the corpus luteum begin to produce progesterone, which increases the temperature by 0.4-0.8 ° C.
The maximum level of progesterone is observed 7-9 days after ovulation. If fertilization has not occurred, this is reflected on the graph by a slight drop in basal temperature 3 days before menstruation.

On the graph along the axis Y mark the temperature value, and along the axis X- days of the menstrual cycle (you can mark the days of the month next to them). One menstrual cycle - one schedule. For convenience, the days of menstruation, sexual intercourse, general increase in temperature and other conditions can be noted directly on the chart in special marks. You can draw the graph yourself on a sheet of squared paper, or use ready-made printed or computer versions.

With a normal menstrual cycle, the basal temperature chart can be used to determine when ovulation occurred and the duration of the follicular and luteal phases.

If pregnancy has occurred, the basal temperature continues to remain relatively high (more than 37.2 ° C). This property can be used in practice when menstruation is delayed and the pregnancy test is still negative. If the morning rectal temperature persists, pregnancy may be suspected.

Luteal phase deficiency

With inferiority of the corpus luteum or low concentration of the hormone progesterone, insufficiency of the second phase of the cycle is observed. This is manifested by a low increase in basal temperature after ovulation, a short (less than 10 days) luteal phase.

When the second phase of the cycle after ovulation is shortened, the rise in temperature is delayed and shortened. The duration of the second phase is no more than 10 days.

Anovulation (lack of ovulation)

During anovulation, the basal temperature remains monotonically low throughout the entire cycle. If ovulation does not occur, the corpus luteum, which synthesizes progesterone, does not form. The consequence of this is the absence of an increase in basal temperature on the graph.

Conclusion

The method of constructing basal temperature is visual, simple, cheap, and gives an idea of hormonal imbalance in a woman, but one cannot draw conclusions based only on its results. There are many errors and exceptions. Therefore, for a final diagnosis and subsequent selection of therapy, it is necessary to use other methods (ultrasound with folliculometry, study of hormonal status in different phases of the cycle, ovulation tests).

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 BT 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.