During a woman's menstrual cycle, the uterus undergoes changes under the influence of female sex hormones. The most important changes occur in the endometrium of the uterus. There is a complete restructuring of its structure, preparation for possible pregnancy and menstruation.
The structure of the uterus is represented by three layers: internal (endometrium), middle (myometrium) and external (perimetric). The uterus inner mucosa normally consists of two levels of the epithelium: functional and basal. Penetrate his many blood vessels. Under the action of hormones, the inner lining of the uterus undergoes changes in the structure, changes its thickness. The purpose of these transformations is to prepare the uterus for implantation of the embryo during fertilization. The process of adjustment and changes in the thickness of the shell occurs during the entire menstrual cycle. You can trace using the M-echo of the uterus.
This study can be differently called ultrasound examination of the uterus and its structure. The principle of operation is that a special sensor radiates an ultraviolet flux that penetrates the uterus, is reflected from its structures, and the response signals are recorded on the screen of the device as an image. The main trait evaluated is endometrial thickness. Normal mucous during a cycle goes through three phases:
- The initial or bleeding phase (start of the cycle).
- Medium or proliferative (phase of growth and restructuring).
- Ultimate or secretory.
Each of them includes several periods, each phase and day corresponds to a specific thickness of the endometrium by days of the cycle. If the M-echo corresponds to the norm, it can be concluded that the hormonal balance in the body and the normal course of the period in a woman’s life.
Consider specific changes in the inner lining and follicles in phases and days.
As is known, the cyclic period of a woman always begins with the first day of menstrual bleeding. This bleeding is associated with rejection of the functional layer of the endometrial membrane. This period of time lasts on average from five to seven days, includes two periods: the stage of desquamation (rejection) and regeneration. Endometrial thickness by cycle days in the first phase:
- In the stage of rejection on 1 and 2 day of the cycle, the thickening is from 0.5 cm to 9 mm. On the M-echo, we see the mucosal hypoechogenicity (decrease in density), since a layer is lost. Accompanied by bleeding.
- In the stage of recovery or regeneration, which occurs on the third - fifth days, the epithelium shows the smallest height, respectively days, only 3 mm (on the third day) and 5 (on the fifth).
The proliferation stage starts from day 5 and lasts up to 14–16 days. The endometrium grows, rebuilds, prepares for ovulation, fertilization and implantation of the egg. Three periods, including different dates:
- From the 5th to the 7th day of the phase (early proliferative stage) - the normal epithelium of the uterus on the M-echo is hypoechogenic (density is reduced), its height is from 5 to 7 mm. On the sixth day - 6, on the seventh about 7 millimeters.
- In the average proliferative period, the mucous membrane changes as follows: thickens, expands. On day 8 already 8 mm high. This stage ends on the 10th day, the epithelium reaches a value of 1 centimeter (10–12 millimeters).
- From day 10 to day 14, the proliferation stage ends. The inner lining of the uterus at this point is normally between 10 and 12–14 mm in height (almost 1.5 centimeters). The density of the layer increases, which is manifested by an increase in echogenicity. In addition, at this time begins the maturation of the follicles in the egg. On day 10, the follicle is 10 mm in diameter, by 14–16 days already up to 21 millimeters.
This period is the longest and most important. It runs from 15 days to 30 (with a normal duration of the cycle). It can also be early, middle and late. The structure changes significantly:
- From 15 to 18 days begins early restructuring. The mucous layer grows slowly, gradually. On average, the values are different. Thicken from 12 to 14–16 mm. On the M-echo layer looks like a drop. Along the edges hyperechogenic, and in the center of the density is reduced.
- The average period of secretion runs from 19 to 24 days. The endometrial envelope maximally thickens to a level of 1.8 centimeters; it should not be greater than this value. The average value for this time is from 14 to 16 mm.
- Finally, the late secretory stage lasts from day 24 until the beginning of the next first phase. Gradually decreases the size of the shell to about 12 mm or slightly below. The peculiarity is that it is at this time that the highest density of the mucous layer is, we see a hyperechoic uterine region.
With a delay
When a girl has a menstruation delay (onset of bleeding), her cyclic period is prolonged. The most common cause is hormonal failure. The reasons for this are: stress, eating disorders: not so much the diet, as consumption of vitamins, gynecological diseases, endocrine diseases, and so on.
When the delay does not produce the necessary hormones, the uterine epithelium remains in size, which was in the secretion phase (from 12 to 14 tenths of a centimeter), and does not reduce its height to the desired value. There is no rejection, respectively, do not begin monthly.
Standard endometrial thickness by cycle days
Every month a woman goes through a cycle. During this time, the shell goes through three phases of development:
During these phases of development of the uterine layer, each of them is divided into three more:
Further, its development is observed by the days of the cycle. Below is a table with the size of the uterine membrane in millimeters for each day.
Let's take a closer look at what happens with this layer in each of these periods.
By the time corresponds to early secretion. During this period, the growth of the functional layer slows down, but a slight thickening still occurs. On average, the width of the reservoir reaches about 1.2 cm, while the oscillations are 10-1.3 cm. On ultrasound, it takes the form of a “drop”. That is, in the uterus, the membrane is wide, and to the neck - narrows. Echogenicity is increased compared with late proliferation.
on the 24-28 day
Period of late secretion. The size of the endometrium begins to decrease to an average size of 1.2 cm. During this period, there is a hyper-elevated echogenicity and heterogeneity of the structure. The ultrasound clearly shows the boundaries between the new and the old layer.
As you can see, there are optimal allowable gaps in the seal of the uterus, which do not affect the health and pregnancy of women. However, there are times when it does not meet the standard. What does this mean?
Why does the endometrium not correspond to the phase of the cycle?
Deviations of the actual thickness from the standard occur due to two factors:
- Functional. The discrepancy occurs due to pregnancy. When a woman becomes pregnant, the endometrium automatically thickens. It is necessary for the proper development of the fetus. Interestingly, thickening occurs immediately after fertilization, even if the fetus is not in the uterus. This happens on the 7th day of pregnancy. The highest rate of obesity in the reservoir on the 30th day of pregnancy. It reaches 20 mm in width.
- Pathological. This group of factors that lead to a discrepancy in the size of the layer on the norms of the cycle, has a number of reasons:
- Delay. This problem has many causes. If it is not a pregnancy, the delay may occur due to hormonal disruption, stressful situations, diets, etc. During the delay, the shell no longer grows, but remains the same thickness as at the late secretion stage. During the delay, he does not respond to hormonal changes in the body.
- Hyperplasia. With this disease there are deviations. Manifestation of the disease excessive growth of the inner layer. Its indicators are much higher than those that should be on the table. The disease is treated with the use of hormone therapy. If the treatment is not successful, then apply surgery. If you start the disease, the consequences can be very serious, even cancer.
- Hypoplasia. The disease is manifested by a deviation of the size of the inner layer in the lower side. There is a lack, that is, an excessive “thinness” of the layer. Because of this, a woman’s pregnancy will not come, as there are no favorable conditions for the attachment of the fetus. Usually for treatment and pregnancy increase the inner lining of the uterus. Assign Duphaston.
- Polyps. With these benign growths, the size of the endometrium changes as well. It increases compared with the norm.
- Menopause. This is a special period in which the actual size will no longer meet the standard. When menopause occurs a lack of hormones. If there are few hormones, then the reservoir size is minimal. In this period, 0.5 cm is considered the norm. If the endometrium grows to the size of 0.8 cm, then it is removed by curettage.
The structure of the inner layer of the uterus
The uterus is a hollow organ of the reproductive system that performs the most responsible function in the process of pregnancy. Outside it is covered with a shell, which is called perimetry. In the middle the genital organ is lined with myometrium.
Due to this muscle layer, the uterus shrinks during pregnancy, childbirth and menstruation. The interior is functional and is called the endometrium. This layer is extremely important for the performance of the main tasks: monthly menstruation, conception and carrying a fetus.
The thickness of the endometrium is an important parameter by which you can determine the performance of the genital organ and appendages. Under the action of hormones in the first phase of the cycle, the mucous surface increases in volume, and with the onset of the next bleeding in the absence of pregnancy, it is separated and exits through the cervical canal.
The inner layer of the reproductive organ, in turn, is divided into two parts:
- basal, which is directly adjacent to the myometrium and is the foundation for the division of new cells in the subsequent menstrual cycle,
- functional, the task of which is an increase in the volume for acceptance of the ovum and rejection in the absence of pregnancy.
The basal layer is practically unchanged and is slightly regulated by changing hormonal levels. Its thickness is constant and is about 1-1.5 mm.
How and why is it measured?
The thickness of the endometrium is determined using a sonographic study, which is more commonly known by the abbreviation of ultrasound. Diagnosis involves the use of a special sensor and can be performed transvaginally or abdominally. Characteristics of the mucous layer gives the corresponding echogenicity. During the procedure, the specialist measures the area located above the basal layer covering the myometrium.
The purpose of the diagnostic procedure is to determine the functionality of the reproductive system. If it can be seen that the endometrium has a normal thickness corresponding to the days at the beginning and at the end of the cycle, then it can be concluded that the ovaries work well and that there are no pathologies in the uterine cavity. Research conducted by women who are planning a pregnancy or those who use hormonal drugs. The thickness of the layer must be indicated in the protocol of a comprehensive examination of the pelvic organs and is an indirect indicator of the health of the woman.
How does this relate to conception?
It is difficult to overestimate the role of the functional layer of the uterus for conception. A fetal egg is implanted in this segment, provided it has a good thickness. During the subsequent weeks of gestation, vessels are formed from the mucous layer to feed the new organism and a placenta is formed. If the endometrium is not sufficiently lush, then the fertilized egg simply will not be able to attach to it. As a result, pregnancy will not come even if the sperm is merged with the egg. Not in all cases, the thickness of the endometrium with infertility is small. Sometimes it's the other way around. If it is higher than normal, pregnancy also will not come. And if implantation takes place, there will be a big risk of interruption or development of pathologies during gestation.
In medicine, it is established what the thickness of the endometrium is normal and which is insufficient or excessive. If during the ultrasound revealed deviations, they must be corrected. With the help of drugs, this parameter can be regulated, which is especially important when planning conception.
Normal endometrial thickness by cycle days
The menstrual cycle is divided into several phases, which determine the state of the mucous layer. The normal thickness of the endometrium of the uterus is set for each day.
- During the bleeding phase of a woman, the mucous layer of the uterus goes through two stages: separation (desquamation) and recovery (regeneration). By changing the thickness, the functional surface is updated and prepared for the active growth of fresh cells.
- At the second stage, the endometrium undergoes a proliferation phase. It is divided into early, middle and late. Proliferation is characterized by active growth and cell division.
- The third stage to which the endometrium is exposed is called secretory. During this period, there is no such active growth as in the previous one. However, the mucosa undergoes major changes in preparation for the adoption of the ovum.
The final period will be the onset of pregnancy and the subsequent transformation of the endometrium or the absence of conception and the next bleeding.
1-4 day: bleeding phase
The first day of the cycle is considered the moment when menstruation began. Even if the discharge is not large for several days, the countdown of the new cycle begins anyway. If the first day is incorrectly determined, there may be errors and inconsistencies in the diagnosis and, as a result, an erroneous diagnosis.
The thickness of the endometrium in 1 day of bleeding varies from 4 to 9 mm. During this period, the temporary vascular bed becomes thinner and destroyed. So begins menstruation. The width of the mucous layer in the first two days of the bleeding phase is regulated by the intensity of the menstrual period. By the third day, the desquamation stage is completed, and regeneration begins. The thickness of the functional layer at this time is minimal, ranging from 2-3 to 5 mm. By the fifth day, the bleeding phase is over, despite the fact that some women have menstruation longer. Normal monthly should not be less than 2 or more than 8 days.
On the 5th day from the beginning of bleeding, the proliferation phase starts. In some women, it may begin only on the 7th day, but this is rare. The endometrium begins to gradually increase, increasing from 2 mm.
5-7 days are called the phase of early proliferation. Usually the width of the mucous layer at this time corresponds to the day of the cycle. So, on day 6, the endometrium is 6 mm. It has a low density and is evenly spaced. By the end of the week from the start of menstruation, the endometrium is 7 mm.
On the 8-10th day
After the first week of the monthly cycle, the period of average proliferation begins. The actively growing endometrium acquires a more pink layer at this time and gradually increases the density. Normally, if its thickness continues to correspond to the day. Therefore, when performing ultrasound in a healthy woman, a functional layer is found with a thickness of 7-8 mm for 8 days, 8-9 mm for 9 days and 9-10 mm for 10 days. Echogenicity is still reduced, but continues to increase daily.
On the 14th day of the cycle, an average woman ovulates. When the egg leaves the ovary, the ground for accepting the future embryo must be fully prepared. Therefore, late proliferation is completed by the middle of the menstrual cycle. The thickness of the endometrium during ovulation in normal amounts to 14 mm.
If on the 12th day of the cycle to make an ultrasound, it will show in the area of the bottom of the uterus zones of greater thickening. The average value, to which the mucous layer increases in 2 weeks, is 13-15 mm. If a woman has a long menstrual cycle, the first part of which lasts 21 days, then such a size of the mucous layer will be achieved over a longer period.
On days 19-23
The secretory phase to the 19-20 day of the menstrual cycle enters the middle stage. The thickness of the functional layer - endometrium - during this period can vary from 15 to 18 mm. The mucous layer continues to change under the influence of hormonal levels. It undergoes modification: it becomes more dense and wide.
In the case of the merger of the female and male germ cells fertilization occurs. For 6-7 days, while continuing to divide, the new organism moves in the direction of the reproductive organ. The endometrial norm for conception for 20-21 days should be about 16 mm, but this figure can also vary from 14 to 18 mm.
On the 24-28 day
This period is characterized by a late secretory stage. The mucous membrane of the uterus at this time was already determined in the most efficient behavior. When pregnancy occurs, she continues to transform, and in the absence of the ovum, she prepares for the next menstruation.
The thickness of the endometrium before menstruation is 18-20 mm. Less commonly, the height of the shell is 22 mm. The corpus luteum undergoes involution, since pregnancy did not occur. Снижение показателей прогестерона запускает процесс атрофии слизистого слоя. Если в этот период сделать УЗИ, то можно увидеть участки с расширенной капиллярной сеткой и формирующиеся тромбы.Such signs indicate the full preparation of the body for menstruation.
Deviations from the norm
The discrepancy between the thickness of the endometrium and the phase of the cycle can be detected even in healthy women. If the anovulatory cycle is repeated no more than 2 times within one year, then there is no cause for concern. When conducting an ultrasound next month, the situation should be different. When endometrial norms do not correspond to the indicators found in the patient for several cycles in a row, one should look for the cause of the deviations.
If by the middle of the menstrual cycle the thickness of the endometrium is 5 mm, instead of the prescribed 10-15 mm, then the woman will not be able to become pregnant. Underdevelopment of the mucous membrane can have different causes: from stress to serious disorders in the body. Endometrial hypoplasia is characterized by a thinning of the functional layer. At the beginning of the menstrual cycle, the endometrium is 2 mm, as in healthy women, but by the middle and the end it is half the thickness.
Excessive growth of the functional layer is also not a good indicator. The thickness of the endometrium with hyperplasia exceeds 21 mm, and in some areas it can reach 60 mm. If by the middle of the cycle this parameter is equal to 20 mm, then getting pregnant will not work either. A sign of hyperplasia will also be a condition when, after menstruation, the thickness of the endometrium is 18 mm.
The structure of the endometrium and the stages of its development
Endometrium is the lining of the uterus, which covers the inside of the wall. Due to the changes that occur regularly in its structure, women have menstruation. This shell is designed so that the fertilized egg can be kept in the uterus and develop normally. After it is implanted in the mucous membrane, the placenta grows, through which the fetus is supplied with the blood and beneficial substances necessary for its growth.
The mucous membrane of the uterus consists of 2 layers: the basal (directly adjacent to the muscles) and functional (surface). The basal layer exists constantly, and the functional layer varies in thickness every day due to the processes of the menstrual cycle. The thickness of the functional layer determines whether the embryo can gain a foothold, how successfully its development will take place.
During the course of the cycle, changes in the thickness of the endometrium normally undergo several stages. There are the following phases of its development:
- Bleeding (menstruation) - rejection and removal from the uterus of the functional layer associated with damage to the blood vessels of the mucous membrane. This phase is divided into desquamation (detachment) and regeneration (the beginning of the development of a new layer of basal cells).
- Proliferation - the increase in the functional layer due to the proliferation (proliferation) of tissue. This process occurs in 3 stages (they are called early, middle and late).
- Secretion - the phase of development of the glands and the network of blood vessels, filling the mucous membrane with secretory fluids. An increase in mucosal thickness occurs due to its swelling. This stage is also divided into the early, middle and late stages.
The size is influenced by hormonal processes occurring in different periods of the cycle. Matters the age of the woman, her physiological state. Deviations from the norm can occur in the presence of diseases and injuries in the uterus, circulatory disorders. Hormonal disruption leads to pathologies. Indicators of the norm have a fairly large variation, since for each woman they are individual and depend on the cycle length and other features of the organism. A violation is a value that exceeds the specified limits.
For what and how is uterine mucosa measured
Measurement is performed using ultrasound. The study is conducted on different days of the cycle. This allows you to establish the cause of menstrual disorders, to detect tumors and other neoplasms in the uterus, which affect the thickness and density (echogenicity) of the mucous membrane, as well as its structure.
An important point is the determination of these indicators in the days of ovulation in the treatment of infertility. In order for the fertilized egg to gain a foothold in the uterus, the thickness of the functional layer should not be less than 7 mm. Its value in this case is determined approximately on the 23-24 day of the cycle, when it is maximum.
Such a study is made when examining women of any age.
Normal functional layer thickness on different days of the cycle
During the cycle, mucous thickness varies literally every day, however, there are average thickness indicators, which can be used to determine how well a woman’s reproductive health condition is normal.
As can be seen from the table below, with the onset of menstrual bleeding (during the first two days of the cycle), the thickness of the mucous membrane reaches a minimum (approximately 3 mm), after which its gradual growth begins. At the stage of regeneration, a new layer is formed due to division of the basal cells. The maximum value (an average of 12 mm) thickness normally reaches a few days after ovulation. If fertilization has occurred (on the 15-17th day of the cycle), then by this time (after 21 days) the conditions most favorable for implantation of the embryo into its wall are created in the uterus.
Uterine mucosa thickness table is normal
Phases of endometrial development
Days of the cycle (developmental stage)
Stages of development of the endometrium
The process of cyclical changes in the uterus in a woman’s body occurs monthly. The size of the endometrium varies depending on the stage of the monthly cycle. There is a division of the menstrual cycle into phases:
- bleeding stage - desquamation,
- the phase of change of the basal area is proliferation,
- functional surface growth - secretion.
At the 1st stage, the process of rejection begins, the upper (functional) layer is removed. First, detachment occurs, then the recovery process begins. The new layer begins to actively develop from the cells of the basal layer.
In the second stage, the functional layer increases, tissues grow. Only 3 stages, which he passes monthly - early, medium, late.
In the third stage, blood vessels and glands develop. Mucosa thickens, this contributes to its swelling. The process is also divided into 3 stages - early, middle, late. In gynecology, there are average indicators of the norm for the size of the mucous layer of the uterus.
How and why measure the thickness of the mucous layer
To know the thickness of the endometrium can not be on a preventive examination at the gynecologist. The specialist prescribes ultrasound, calculated for a specific days of the menstrual cycle. In the process, the doctor sees the state of the uterus, can detect tumors that are in the body, factors affecting the thickness and density of the endometrium. It studies the structure of the mucosa.
Women who are faced with the problem of conception, infertility, must know these indicators. Ultrasound is prescribed on ovulation days. Thickness values change daily during the monthly cycle. Professionals have roughly averaged values that can show the state of the reproductive function of a woman, what problems there are.
A special table has been developed that has such indications; according to it, a specialist can see how the patient’s indicators differ from the approximate normal values. It should be noted that a deviation, pathology is considered to be a big difference between the available and averaged indicators, from which experts repel.
The norms for the phases of the menstruation cycle
Endometrium grows in accordance with the phases of the cycle. Ultrasound allows you to track performance, it is assigned in different periods of the menstrual cycle, because the thickness of the mucous layer differs in the phases of the cycle. The results of the study allow a specialist to assess the internal state of the body. Depending on the size of the endometrial layer, the specialist makes a diagnosis. There is an average figure, which is considered the norm, but in each individual case, it may differ.
The proliferation phase begins on the 5th day of the cycle. Its duration is up to 14-16 days. Endometrial layer increases. In the second phase of the cycle there are 3 periods:
- early - from 5 to 7 day of the cycle. On the 5th day the layer thickness is 5-7 mm, on the 6th day - 6 mm, on the 7th day - 7 mm,
- medium - during this period, the endometrium begins to actively grow, thicken. On day 8, its size is 8 mm. The end of the stage falls on the 10th day of the cycle, the size is 10-12 mm,
- final - this stage ends the period of proliferation, it lasts from 10 to 14 days of the cycle. The thickness of the functional layer increases, the height of the uterine lining reaches 10-12 mm. The process of maturation of follicles in the egg cell begins. The diameter of the follicles on the 10th day - 10 mm, on the 14-16 day - about 21 mm.
When menstruation is delayed, its cyclic period is extended. Often this provokes a hormonal failure. Factors such as stressful situations, unhealthy diet, problems of the endocrine system, gynecological diseases cannot be excluded.
In the process of delay in the body, the necessary hormones are not produced, the size of the uterine epithelium is maintained at the level of the secretion phase. The average value is 12-14 mm. There is no decrease in this indicator, the process of rejection, menstruation does not occur.
If the egg is not fertilized - the functional layer exfoliates during menstruation. If a woman becomes pregnant, then the normal thickness of the endometrial layer in the first days remains at the same level. After a few weeks, the figure rises to 20 mm. After a month of pregnancy, an ultrasound can show a small fruit egg.
If a woman faces a delay, and pregnancy tests show a negative result, you can learn about it by the level of increase in the mucous membrane, 2-3 weeks after the embryo is fixed on the walls of the uterus.
What to do if the thickness does not match
The inconsistency in the thickness of the endometrium is detected by the doctor during an ultrasound scan. It is often observed during pregnancy, the mucous membrane is overgrown with vessels. By the 2nd week of pregnancy, the layer grows to 2 or more centimeters. Any changes in thickness may be pathological. There are two types of violations:
- endometrial hypoplasia - for therapy use drugs with a large amount of estrogen. Aspirin is also prescribed in small quantities. Well proven in the treatment of pathology leeches, acupuncture, physiotherapy. Experts note the stimulation of endometrial growth using sage,
- hyperplasia - hormone preparations are used as drug therapy. It is possible surgical intervention (curettage) of an excessively large mucous layer. In the most severe cases, women are offered removal of the uterus. Combination therapy (curettage and hormonal preparations) show high results.
The mucous layer undergoes the greatest changes during menstruation, and female sex hormones contribute to this. If there is no imbalance in the hormonal background, menstruation occurs without deviations.
What is the thickness of the scraping
Endometrium is a 2 layer - functional, basal. It is the functional layer and the vessels under it that a woman sees when menstruation is proceeding. If fertilization does not occur, this layer exfoliates and leaves during menstruation, the blood appears as a result of rupture of blood vessels. When hyperplasia is an increase in the layer of its cells.
When the endometrial layer reaches 26 mm, its structure changes, active cell division occurs, it is necessary to make curettage, which helps to eliminate the strong bleeding that accompanies menstruation. This prevents the formation of malignant cells, and hormone therapy reduces the risk of recurrence.
Among the most common pathologies of the endometrium, experts note two - hypoplasia and hyperplasia. Both pathologies have different characteristics and methods of treatment.
Endometrial hyperplasia is a pathology, during which there is a thickening of the upper (functional) layer of the uterine mucosa to (26 mm), compaction, change of structure. Hyperplasia prevents, does not allow to consolidate a fertilized egg in the uterus, the fetus does not have the opportunity for development.
Pathology often provokes a failure in menstruation, its duration, intensity of discharge is disturbed. Often it provokes the development of anemia, a woman observes a blood-bleeding during the period between menstruation of different intensity. An enlarged endometrial layer often becomes the prime cause of the appearance of polyps and other neoplasms.
The thinned endemetric shell does not allow a woman to realize her reproductive function — to become a mother. Hypoplasia interferes with the egg being fixed on the uterine wall. The egg cell does not receive the necessary nutrition that the system of blood vessels provides, which is why the fetus dies some time after its formation. Thin mucous often becomes the cause of the development of inflammatory, infectious processes in the uterus, because it becomes less protected from the penetration of various microorganisms. Hypoplasia often causes weak development of the external genital organs, ectopic pregnancy.
The process of changing the endometrium is one of the most important in a woman’s body. It correctly goes through all periods if hormonal balance is normal. When the first deviations, deterioration of health should consult a doctor. Maintaining one's health is an important task that every woman should pay enough attention to.