Ovulation is a process that takes place in the body of a healthy woman, which is associated with the release of an egg into the fallopian tube for further fertilization. Knowing the day you start ovulation can help plan your pregnancy or prevent an unwanted conception. There are several methods for determining it, but the most affordable and simple is to measure basal body temperature.
What is it?
Basal body temperature (BTT) is an indicator that is measured in a state of complete rest, in the anus, immediately after morning awakening. It is a reflection of the hormonal background of a woman and allows you to identify problems in the work of the genital glands. However, more often BTT is used to determine the days favorable for conception.
Many gynecologists advise women to maintain their basal temperature schedule. Especially for those who plan replenishment in the family. The graph of basal temperature during ovulation has its own characteristics. It allows you to calculate the most suitable day in order to get pregnant. Basal temperature directly depends on hormonal processes in the body of a woman.
The menstrual cycle and its phases
The female body was created to continue procreation, so all the processes taking place in it are aimed at ensuring conception and preparing the body for pregnancy and childbirth. The menstrual cycle consists of three consecutive phases: it is follicular, ovulatory and luteal.
The first phase begins with menstrual bleeding, followed by the formation of a follicle in the ovary and the formation of a new endometrium. Its duration can suggest a basal temperature graph. Its normal duration is 1-3 weeks. In this phase, the phyllic stimulating hormone and estrogen play a role. It ends with the maturation of the follicle.
The second phase is ovulation itself. The walls of the follicle are torn, and the egg passes through the fallopian tube towards the sperm. The phase lasts about 2 days. If fertilization occurs, the embryo attaches to the endometrium; if not, the egg dies. On a normal schedule, basal temperature on the day of ovulation is at its lowest level for the entire cycle.
In the third phase, progesterone production begins. It is produced by the corpus luteum, which was formed on the site of a ruptured follicle. The basal temperature after ovulation changes upwards - by 0.4-0.6 ° C. During this period, the female body prepares for bearing and preserving the fetus. If conception has not occurred, then the concentration of female sex hormones decreases, and the circle closes, the follicular phase sets in. Its duration in normal for all women is about 2 weeks.
Why are temperature fluctuations?
Measurement of basal temperature during ovulation as a method characterizing hormonal changes in the body of a woman was proposed in 1953 by the scientist Marshall. And now WHO has been approved as an official way to detect fertility. Its basis is a regular change in the concentration of progesterone in the blood. This hormone acts on the thermoregulatory center in the brain, which causes a local increase in temperature in the organs and tissues of the pelvis. That is why a sharp increase in temperature in the anal part occurs in the luteal phase.
Thus, ovulation divides the menstrual cycle into two parts: in the first, the average temperature is approximately 36.6-36.8 ° C. Then it drops by 0.2-0.3 ° C for 2 days, and then rises to 37-37.3 degrees and remains at that level almost until the end of the cycle. The normal basal temperature graph during ovulation is called biphasic.
Measuring BTT can help determine with high accuracy the day that is successful for conception. According to statistics, it is known that the greatest chance of getting pregnant will occur a day before and after a fever - 30% each. 2 days before the jump - 21%, 2 days after - 15%. Pregnancy can occur with a 2% chance if fertilization occurs 3 or 4 days before the temperature rises.
What is this method used for?
If you constantly draw up a graph of basal temperature, the norm and pathology begins to be traced literally in 2-3 cycles. The resulting curves can provide answers to many questions. Therefore, gynecologists strongly recommend this method to solve the following problems:
- Determination of a favorable day for conception.
- Early diagnosis of pregnancy.
- As a way of contraception.
- Identification of malfunctions in the gonads.
Basically, basal temperature is measured to calculate the day the ovulatory phase of the cycle begins. This is the easiest and cheapest way. It is very easy to determine ovulation at basal temperature if you regularly take measurements and follow all the rules.
Correct measurement is the key to the effectiveness of the method
In order for the results of the method to be true, it is necessary to follow all instructions when measuring BTT, because it is very important that the basal temperature chart during ovulation include only accurate and reliable data. There is a set of basic rules:
- Temperature measurement is carried out daily at the same time (optimally - 7.00-7.30) in the rectum.
- Before the procedure, you must sleep at least 3 hours.
- If a woman needed to get out of bed before the time of measurement, then the testimony should be taken before taking a vertical position.
- The thermometer must be prepared in advance and put near the bed. Shake it off better before going to bed.
- Temperature can be measured only in a horizontal position, lying motionless on its side.
- During the cycle, you can not change the thermometer.
- It is better to enter readings in the graph immediately after the measurement.
For measurements, both a digital and a mercury thermometer are suitable. But an infrared thermometer is absolutely not intended for this method, because it has a high probability of an error in the results. Since the basal temperature before ovulation and on the day it begins differs by only 0.2-0.3 ° C, such a thermometer may not show this difference. An electronic thermometer gives large errors if you do not follow the instructions for its use. The most accurate indicators can be obtained using a mercury thermometer, but it requires special care when handling.
When the obtained indicators may be incorrect
It must be remembered that the basal temperature during ovulation, the norm of which is individual for each woman, can fluctuate depending on the influence of various factors. Often external influences on the body lead to the fact that BTT indices are strongly distorted and have no informative value. These factors include:
- Flights, travels, business trips.
- Stress.
- Excessive alcohol intake.
- Acceptance of psychotropic and hormonal drugs.
- Inflammatory processes in the body, fever.
- Increased physical activity.
- A short dream.
- Non-observance of measurement instructions.
- Sexual intercourse a few hours before the measurement.
If something from the above list happened, then you should not trust the measurements. And the day on which there was a violation can not be taken into account in the construction of the schedule.
How to plot a basal temperature graph
To plot a basal temperature, it is necessary to take measurements every day and make entries in a specially designated notebook. The graph represents the intersection of two lines at a right angle. The vertical axis contains data on temperature, for example, from 35.7 to 37.3 ° C, and on the horizontal axis there are days of the menstrual cycle. Each cell corresponds to 0.1 ° C and 1 day. After measuring, you need to find the day of the cycle on the graph, mentally draw a line up and put a point in front of the desired temperature. At the end of the cycle, all points of the graph are connected, the resulting curve is an objective reflection of hormonal changes in the female body.
The graph should indicate the current date and build a column for special notes. In order for the data to be sufficiently complete, you can describe your well-being, the symptoms that appear or situations that could appear on a change in basal temperature.
If a woman is not very clear how to plot a basal temperature, then the gynecologist from the antenatal clinic will definitely explain how to do this, and also help to decipher the data.
Now there are many programs with which you can create an electronic schedule, which will always be at hand. In this case, the woman just needs to enter the temperature indicators. The program will do the rest.
Decoding graph
In this method of determining fertility, it is important not only to construct, but also to decipher the basal temperature graphs. The norm for each woman is individual. However, there is an approximate form of the schedule, which should be obtained if the sex glands are working properly. To analyze the resulting curve, you need to build the following elements: overlapping line, ovulation line, duration of the second phase.
The overlapping (middle) line is built on top of the 6 points of the follicular cycle without taking into account the first 5 days and days when the indicators deviated strongly due to external factors. This element is not meaningful. But necessary for clarity.
The basal temperature on the day of ovulation decreases, so to determine the day for a successful conception, you need to find consecutive points that are under the overlapping line. In this case, the temperature values of 2 out of 3 points should differ by at least 0.1 ° C from the midline, and at least 1 of them should have a difference of 0.2 ° C with it. The day after this, you can observe a jump of a point up 0.3-0.4 degrees. In this place, you need to build a line of ovulation. If you have any difficulties with this method, then you can use the “finger” rule to build a graph. For this, it is necessary to exclude all points that differ by 0.2 degrees from the previous or next indicator. And on the basis of the obtained graph to build a line of ovulation.
The basal temperature after ovulation in the anus should be kept above 37 ° C for 2 weeks. Deviations in the duration of the second phase or a small jump in temperature indicate a malfunction of the ovaries or low productivity of the corpus luteum. If 2 consecutive cycles, the duration of the second phase does not exceed 10 days, then it is necessary to consult a gynecologist, since this is the main sign of progesterone deficiency of the luteal phase.
The graph of basal temperature during ovulation should also correspond to the norm in such a parameter as the temperature difference between the follicular and luteal phase. This indicator should be equal to more than 0.4 ° C.
What does the graph look like in the presence of ovulation and in pathologies
A normal ovulatory chart consists of two phases. In the first one, one can observe an average temperature of 36.5-36.8 ° C for 1-3 weeks, then a drop of 0.2-0.3 ° C and a sharp rise to 37 ° C and above. In this case, the second part of the schedule should be no shorter than 12-16 days, and before the onset of bleeding, a slight decrease in temperature is observed. Graphically, it looks like this:
You should also give examples of basal temperature graphs in which pathology is traced. The curve will differ from the norm in various ways. If estrogen-progesterone deficiency occurs , then the temperature jump will be no more than 0.2-0.3 ° C. Such a condition is fraught with infertility, therefore, it requires an appeal to specialists.
If the second phase on the chart is shorter than 10 days, then this is a clear sign of progesterone deficiency. Usually, there is no decrease in temperature before the onset of menstrual bleeding. In this case, pregnancy is possible, but under the threat of interruption.
If there is a lack of estrogen in a woman’s body, then the schedule will have a chaotic character, dramatically different from the norm. It can also be due to the influence of external factors (flights, excessive alcohol intake, inflammation, etc.).
When the curve does not have sharp temperature jumps and is a monotonous graph, then this is called an anovulatory cycle. This happens in healthy women, but not more often 1-2 times a year. If this is repeated from cycle to cycle, then this may be a sign of infertility.
If, after the second phase, there is no decrease in temperature, then most likely the woman is pregnant.
Deciphering the basal temperature graphs, examples of which are presented above, require specialist knowledge. Therefore, you should not draw conclusions yourself, make a diagnosis and prescribe treatment.
Advantages and disadvantages of the method
The advantages of the method are its absolute availability, simplicity and complete absence of costs. When the baseline temperature chart for ovulation is maintained by a woman regularly, this makes it possible to determine the days of ovulation, recognize an early pregnancy in time, or detect hormonal abnormalities and consult a gynecologist.
However, there are also disadvantages in the method. This method is not very accurate due to the individual characteristics of each organism. Here are its main disadvantages:
- It does not make it possible to predict when the ovulatory phase will begin.
- It does not provide accurate information about when ovulation was.
- It does not guarantee even with a normal biphasic schedule that ovulation really was.
- It can not give specific information about the quantitative content of progesterone in the blood.
- It does not provide data on the normal functioning of the corpus luteum.
To know exactly how informative the method is, it is necessary to take blood tests for female hormones in the first couple of cycles and make an ultrasound. If the data of the schedule and studies coincide, then a woman can safely keep a schedule of basal temperature. The norm and deviations displayed on the curve in this case will correspond to reality.
This method is convenient, simple and does not require financial expenses. If you strictly follow all the rules and know how to decipher the basal temperature graph, then figuring out the day of ovulation and planning the conception is very easy. However, if there are any deviations from the norm, you should consult a specialist to prevent the development of pathological processes.