Normal basal temperature in pregnancy: chart

Menstrual cycle in women, which on average lasts 28-35 days, can be divided into 2 phases: pre-ovulatory and postovulatory. In the first phase of the sexual cycle in a healthy woman is usually not observed alarming temperature fluctuations. In her ovaries under the influence of estrogen gradually mature eggs (usually 1 per month), which is not accompanied by a rise in temperature. On the contrary, in the early days of menstruation can be noted some of its decline, but during the entire first phase of basal temperature fluctuations are kept within the limits of 36.1 - 36.8 degrees. If it becomes higher, it indicates either inflammation in the genital system or a deficiency of estrogen, which, as we know, reduces the body temperature.

If you follow the graph of basal temperature during the first phase of a woman's cycle when planning a pregnancy, you can see how it gradually decreases during the first week, which indicates an increase in the production of estrogen, necessary for the maturation of the egg, and a decrease in the synthesis of progesterone. To some, this moment may seem insignificant, because pregnancy is judged by the second phase of the cycle, which and pay more attention. In fact, the temperature changes of the first phase can already be judged on the functioning of the endocrine system and, in particular, the sex glands. If there is a lack of estrogen (temperature above 36.8 degrees Celsius), the ovum may simply not mature, and it is useless to wait for pregnancy in this case, although the problem is usually solved by the simple introduction of substitutes for the female hormone.

When the egg is mature and ready to go "into the world", the day before ovulation or on the same day, the woman's body temperature drops noticeably to 36 - 36.2 degrees (the reason lies in the same estrogen, which during this period are released in maximum quantity). After the egg leaves the follicle, the need for increased production of estrogen decreases, but there is a need to preserve a possible pregnancy. In place of the ruptured follicle, the corpus luteum appears and the synthesis of progesterone begins, which at this stage is more important for the maintenance of a possible pregnancy. This causes a consistent increase in body temperature during the second phase of the menstrual cycle up to day 21-25 of the menstrual cycle, after which it either falls (if conception has not occurred), or remains elevated and further (if pregnancy occurs). [1]

There is no need to be frightened by the rise in basal temperature in the second phase when planning pregnancy. This is a common physiologically conditioned process, and the temperature difference is not so high. The interval between the highest temperature of the 1st phase of the cycle and the maximum reading of the thermometer in the second phase is usually 0.4-0.5 degrees.

Preovulatory drop in temperature after the rupture of the follicle is accompanied by a sharp rise in temperature (the fact that before the appearance of the corpus luteum, progesterone is synthesized and accumulated in the follicle, and after its rupture is released into the blood, which causes a sharp jump in temperature, although on the first day it rarely rises to 37 degrees Celsius). It is on this temperature spike in the middle of the cycle just and should pay attention to those women who want to get pregnant, because it indicates ovulation and the optimal opportunity to become a mother.

Later, thanks to the luteinizing hormone, which enters the blood on the eve of ovulation, formed the corpus luteum, which as it develops and increases the concentration of progesterone in the blood, which means that the temperature continues to rise, reaching values of 37.1 - 37.2 degrees (sometimes up to 37.7, which is not considered a pathology, if not kept too long).

After 21 days of the cycle, in the absence of fusion of the ovum and sperm, the gland, called for its color yellow body, becomes unnecessary, it gradually atrophies and is removed from the body during menstruation. During this period, there is a gradual decrease in the production of progesterone and, accordingly, a decrease in body temperature even before the onset of phase 1 of the next menstrual cycle.

If conception has occurred, the gland actively functions for another 2.5-3 months, and sometimes even longer, thus preventing pregnancy failure. Ask doctors the question, what should be the basal temperature in pregnancy, and they will answer not specifically, because normal is considered and the temperature of 37.1 degrees, and a couple of tenths of a degree more - 37.2-37.4.

To a large extent, these indicators depend on the individual characteristics of the body of the future mother, the activity of the processes occurring in it, because even in the absence of hormonal changes associated with pregnancy, body temperature in different people at rest can differ by 0.1-1 degrees. It is not surprising that potential moms can establish an individual temperature, and if it does not deviate from the norm by more than 0.8-1 degrees, there is no cause for concern.

If the basal temperature after conceiving a child is slightly different from the norm (the generally accepted norm is 37.1-37.3 degrees), do not worry in vain, because the individual norm can be determined only in comparison with the usual temperature. For example, if in the 1st phase of the cycle the temperature of a woman did not rise above 36, 5 degrees, then in the 2nd phase it is unlikely to be higher than 37.

It should be noted that it makes sense to talk about what should be the basal temperature in pregnancy in the morning after waking up, in the evening it is not logical to measure it, because the body spends energy during the day, is exposed to the influence of internal and external factors, so the results of measurements will not be adequate. Tips to measure the basal temperature in pregnancy twice a day have no logical basis. Evening measurements will be different from morning measurements, and between each other, regardless of how the pregnancy proceeds. [2]

Basal temperature and pregnancy

Measuring the basal temperature is considered an accessible and quite effective method of diagnosing pregnancy, which allows you to detect it from the very first day without additional instrumental and laboratory tests. Usually, a woman learns about pregnancy by the absence of menstruation at the proper time and a few days after the planned onset of menstruation.

Basal temperature with its regular measurement allows you to learn about pregnancy even before the delay. After all, most often the interval between conception and the beginning of the next period is about 14-16 days, during which the egg has time to undergo several divisions, change its place of residence and get fixed in the uterus. During this period, the future child's nervous system and some organs are formed, even if it still looks little like a human being, but it will definitely become one with the help of mom.

Until the placenta forms around the embryo, which later becomes an embryo, the corpus luteum will be responsible for its preservation, producing progesterone in sufficient quantities. This hormone on the eve of implantation prepares the uterus for the introduction of a fertilized egg, further restrains its excessive activity and premature contractions, prevents rejection of the embryo as a result of incorrect work of the main defender of the body - the immune system, which considered it a foreign body. Progesterone also promotes the production of other hormones that are considered important for the normal development of the fetus. Preserving pregnancy and preventing early delivery. [3]

Not surprisingly, in pregnancy, the basal temperature has higher values both at the onset of pregnancy and in the early stages of pregnancy. How do you know that conception has gone well and there is no need to worry about progesterone levels? Again, by body temperature at rest. Its values during the first month should correspond to those that were established within a week after the day of ovulation. This temperature usually lasts until the period of placentation (end of the 2nd month of pregnancy), and then gradually returns to normal. Although in most cases it remains slightly elevated (within 37 degrees), because the secretion of progesterone in the pregnant body continues, but this function after 12-14 weeks from the beginning of conception is already performed by the placenta.

The beginning of placental secretion of progesterone again causes an increase in its level in the woman's body, because the bigger the baby becomes, the more difficult it is to restrain the activity of the uterus. But the body of the future mother is no longer so acutely reacts to changes in the hormonal background. It develops a certain resistance to progesterone surges, so a marked increase in temperature is not noted until the end of pregnancy, although the concentration of the hormone for all this time increases by 8-10 times. It decreases sharply only before childbirth, which allows the uterus to contract actively. [4]

Basal temperature graph

Speaking about the norm of basal temperature in pregnancy, we noted that not all deviations from the generally accepted norm are considered pathology. Body temperature is an individual matter. Progesterone can change it slightly, based on stable readings for each individual.

It is easy to determine your basal temperature norm by measuring it daily after sleep in the middle of the first phase of the cycle. You should be prepared for the fact that even in a relatively quiet time, when the follicles mature with the participation of follicular progesterone and estrogen, there will be fluctuations in the readings of the thermometer, which is an indicator of the stability of estrogen production. Such fluctuations within 0.5 degrees are quite normal, but what is the basis for calculating the norm of basal temperature?

As a reference point, we take the average indicator, which will reflect our true norm, or the maximum and minimum indicator, which can be used to determine both the lower and upper limits of the norm.

In principle, whether to make a graph of basal temperature when planning pregnancy by day, week, month or just keep a diary, recording in it the results of regular measurements, it is an individual matter. But such records and graphs help to track the dynamics of temperature indicators, calculate the moment of its maximum drop, followed by a sharp increase in values, which indicates ovulation and a good opportunity to conceive a child, effectively protect yourself if the birth of a child is not yet in the plans of the woman and her partner. Not surprisingly, doctors for diagnostic purposes still insist on drawing up a graph (temperature curve), which is later easier to decipher due to the visibility of the results and their changes. [5]

Doctors-gynecologists distinguish such types of temperature curves, by which it is possible to judge the presence of various disorders in the reproductive system and hormonal abnormalities:

• The norm for a biphasic menstrual cycle is a difference of basal temperature in the 1st and 2nd phase of the cycle of 0.4 degrees. In this case, doctors compare the thermometer readings at the time of temperature drop before menstruation and before ovulation. In the postovulatory period, there is a jump in temperature, after which its values are kept at a relatively high level for 12-14 days.
• If the temperature rise in the second phase is weaker (interval 0.2-0.3 degrees), ie, temperature fluctuations are insignificant, it may indicate a lack of production of sex hormones: estrogen and progestoron. Low rate of temperature rise after ovulation indicates that the rupture of the follicle has not occurred, ie, there was no ovulation, the egg in it has not matured.
• When the rise in temperature is observed shortly before the onset of menses, i.e. At the end of phase 2 of the cycle and does not fall on the eve of menses, and the second phase of the cycle is unusually short (less than 10 days), we can talk about the same biphasic cycle, but with insufficiency of the second phase (luteal). In other words, we are talking about violations of the formation and functioning of the corpus luteum, i.e. Progesterone deficiency, as a result of which the fertilized egg is not able to normally fixate in the uterus. This causes spontaneous miscarriages in the very early stages of pregnancy.
• If the temperature curve shows no temperature difference in the two phases of the cycle (monotonic curve), i.e. No noticeable temperature fluctuations in the middle of the menstrual cycle, we speak of an anovulatory (monophasic) cycle. In such women menstrual bleeding may occur regularly, which is perceived as the absence of any pathology. In principle, this is true for adolescent girls in the period of menstruation, pregnant women and breastfeeding mothers.

There are unusual cycles without oocyte maturation and release in mature healthy women due to stress, strict diets, lack of sleep, intoxication, some somatic diseases, hormonal changes (menopause). It is considered pathological if such cycles become regular.

Menstrual cycles without ovulation, which are systematic, can cause infertility. They occur as a result of impaired production of female and male hormones in a woman's body, genetic mutations, polycystic ovaries, impaired functionality of some other pathologies of the reproductive system.

Symptoms of anovulatory cycle can be delays, shifts, absence of menstruation, excessive blood discharge during periods, etc. This allows you to suspect pathology and consult a doctor in time. True, in some cases, changes in the timing and nature of menstruation are not observed, and the woman may suspect violations only on the basis of repeated infertile attempts to become pregnant. To determine whether ovulation occurs, i.e. The maturation and exit of the egg from the follicle, without which it is impossible to conceive a new life, you can use a graph that shows changes in basal temperature during the cycle, or better during several cycles. [6]

• In some women, the temperature curve has such an individual character that it does not fit into any of the types described above. Most often it is random changes and jumps in temperature throughout the menstrual cycle. In contrast to a single-phase cycle, the graph shows a preovulatory drop in temperature followed by a temperature spike in the middle of the cycle, but in other periods the temperature can fluctuate markedly by day.

In such a situation, the doctor may suspect estrogen deficiency, as a result of which there is no temperature balance. In the second phase of the cycle, such women may experience temperature spikes above normal, i.e. Up to 37.6-38 degrees in the absence of pathologies of infectious-inflammatory nature.

Making a basal temperature chart in pregnancy or planning it is a responsible thing to do. For clarity, after drawing points on the graph, one axis of which reflects temperature changes with an interval of 0.1 degrees, and the second counts the days of the menstrual cycle in increments of 1 day, you need to draw 2 lines: the average (horizontal) and the ovulation line (vertical). The middle line is drawn in such a way: throw away the readings of the first 5 days of the cycle and draw a line on the matching temperature readings of the next 6 days. We draw the ovulation line by a couple of cells to the right of the preovulatory temperature drop.

This is all easy to do on a normal chart, when the onset of ovulation is easy to predict (the middle of the cycle, if its duration is known), but we are talking about measuring temperature when planning pregnancy or to increase the effectiveness of contraception. Hormonal disorders in the body tend to change the temperature curve, which complicates its interpretation and requires consultation with a specialist.