Basic Information
Chinese name: menstruation
Pinyin: yuè jīng
Aliases: menstrual cycle, menstrual cycle
Foreign name: Menstrual cycle
Brief overview
The main components of menstruation are blood (3/4 arterial blood, 1/4 venous blood), endometrial tissue fragments and various active enzymes and biological factors. Among them, fibrinolytic enzyme makes menstrual blood liquid and prevents coagulation, and prostaglandins play a role in contracting the uterus. In medicine, it is believed that only the reproductive cycle experienced by primates (including humans) is called menstruation. In addition, the reproductive cycle of other mammals is called the estrus cycle. Menstruation is regulated by the reproductive hormone system, which is the need for biological reproduction. . A woman's first menstrual period is called menarche, and the appearance of menarche marks a woman's puberty. The average age of women at menarche is 12 years. Genetics, diet, health and many other factors can make menarche earlier or later. The cessation of menstruation marks that a woman has entered menopause, also known as menopause. The average age of menopausal women is 51 years old. Of course, just like menarche, many factors such as heredity, disease, surgery and medical treatment can advance or delay menopause. It is normal to enter menopause between the ages of 40 and 58. . The onset of menopause at or before age 35 is defined as premature aging.
menstruation
First of all, we must understand the structure of female reproductive organs and their physiological functions in order to explain this problem.
The female reproductive organs consist of ovaries, uterus, and fallopian tubes. The main function of the ovary is to produce eggs and synthesize ovarian hormones. The uterus and fallopian tubes are reproductive organs. The ovary contains hundreds of thousands of follicles, and each follicle contains one egg.
menstrual cycle
Follicles are largely nonfunctional before puberty. At puberty, under the action of gonadotropins in the anterior pituitary gland, the immature follicles gradually develop and estrogen is synthesized at the same time. When the follicle matures and ovulates, the wall of the oviduct collapses, and the cells become larger and yellowish, called the corpus luteum, which synthesizes estrogen and produces progesterone.
As the ovary changes, the endometrium also undergoes corresponding periodic changes. Estrogen thickens the endometrium, the endometrial cells increase and enlarge, and the small arteries in the interstitium become more tortuous and spiral, which is called the proliferative endometrium. After ovulation, due to the combined action of estrogen and progesterone, the endometrium edema occurs, the glands produce a large amount of mucus and glycogen, and the thickness of the endometrium increases from 1 mm to 6 mm, which is called the secretory endometrium.
If the egg released at this time is fertilized, the fertilized egg is transported to the uterus through the fallopian tube to develop, which is called pregnancy. The pregnancy tissue synthesizes a chorionic gonadotropin, which supports the continued development of the ovarian corpus luteum; if the egg is not fertilized, after ovulation After about 14 days, the corpus luteum atrophies and stops secreting estrogen and progesterone. At this time, the blood vessels in the endometrium contract, the endometrium necroses and falls off, causing bleeding and forming menstruation.
Therefore, the length of the menstrual cycle depends on the length of the ovarian cycle, generally 28-30 days, but it varies from person to person, and there are also 23-45 days, or even 3 months or half a year as a cycle. As long as it is regular, it is generally a normal menstruation.
The bleeding time is generally 2-7 days, and the total amount of each menstrual bleeding is 30-50ml. Some people think that the menstrual flow is more than 80ml is a pathological state.
Cause of formation
Menstruation is regulated by the interaction between the reproductive hormones of the hypothalamus, pituitary and ovary. During the menstrual and proliferative phases of the menstrual cycle, the levels of estradiol and progesterone in the blood are very low, thus affecting the adenohypophysis and lower ovary. The negative feedback effect of the thalamus is weakened or eliminated, resulting in an increase in the secretion of gonadotropin-releasing hormone by the hypothalamus, which in turn leads to an increase in the secretion of follicle-stimulating hormone and luteinizing hormone from the pituitary gland, thus making the follicles develop and estrogen secretion gradually increases. At this point, estrogen stimulates the endometrium into a proliferative phase. Luteinizing hormone increases the secretion of progesterone, leading to ovulation. Estrogen and progesterone levels are elevated during this period. This has a negative feedback inhibition effect on the hypothalamus and pituitary gland, thereby reducing the levels of ovulation-stimulating hormone and luteinizing hormone, leading to corpus luteum involution, which in turn reduces the levels of estrogen and progesterone. Menstruation occurs when the endometrium loses the support of these two hormones and peels off and bleeds. At this point, estrogen and progesterone decrease, and the next menstrual cycle begins.
transformation
The menstrual cycle is regulated by the interaction between the reproductive hormones of the hypothalamus, pituitary and ovary, and the following changes occur during the menstrual cycle:
① After women reach puberty, under the control of hypothalamic gonadotropin-releasing hormone, the anterior pituitary secretes follicle-stimulating hormone (FSH) and a small amount of luteinizing hormone (LH) to promote the development of ovarian follicles and start to secrete estrogen. Under the action of estrogen, the endometrium undergoes proliferative changes;
② The follicles gradually mature, and the secretion of estrogen gradually increases. When the concentration reaches a certain level, it promotes the anterior pituitary to increase the secretion of gonadotropin through the positive feedback effect on the hypothalamus and pituitary, and it is more obvious to increase the secretion of LH. , forming a peak of luteinizing hormone release, which causes mature follicles to ovulate;
③ Under the action of luteinizing hormone, the follicles after ovulation form the corpus luteum and secrete estrogen and progesterone. At this stage, the endometrium, mainly under the action of progesterone, accelerates growth and functional differentiation, transforming into a secretory endometrium;
④ As the corpus luteum secretes a large amount of estrogen and progesterone, the concentration of these two hormones in the blood increases, which inhibits the hypothalamus and pituitary through negative feedback, so that the follicle stimulation and luteinizing hormone secreted by the pituitary decrease, and the corpus luteum shrinks accordingly. Estrogen also decreases rapidly, the endometrium suddenly loses the support of these two sex hormones, collapses and bleeds, the endometrium falls off and menstrual cramps occur.
menstruation
Menstruation, also known as menstruation, moon water, monthly letter, menstrual leave, redness, etc., is called menstruation because most people occur once a month. It refers to regular and periodic uterine bleeding. Strictly speaking, with this bleeding, there should be follicle maturation, ovulation and corpus luteum formation in the ovary, and the endometrium changes from hyperplasia to secretion. However, in clinical practice, there is often a phenomenon of uterine bleeding without ovulation, which is called anovulatory menstruation.
In recent years, common names for menstruation have increased, such as bad things, big aunt, aunt, good things, bad luck and so on. The average age of menarche in modern women is 12.5 years. The age of menopause is usually between 45 and 55 years old, and the reasons are related to various factors such as the aging of ovulation function and the decrease of estrogen secretion. Tiangui refers to menstruation, which can be found in "Ancient and Modern Medical Tradition".
To put it simply, the development of follicles promotes the thickening of the endometrium. If fertilization is not possible after ovulation, the endometrium will fall off, form a menstrual period, and then welcome the next cycle.
Menarche
Overview
In adolescent women, the endometrium undergoes cyclical changes due to the action of sex hormones secreted by the ovaries. It falls off once a month, and the shed mucous membranes and blood are excreted through the vagina. This bleeding phenomenon is called menstruation. Because most people occur once a month and it is called menstruation.
The first menstruation of a girl is called menarche, which is one of the important signs of puberty. The age of menarche is about 10 to 16 years old.
symptom
Menstrual cycle Before menstruation, there are usually some small bloodshots on the underwear.
A woman's body undergoes a series of changes before menarche. If these changes are grasped, the time of menarche can be estimated.
foreshadow
1. Measure weight and height: After girls enter puberty (11-14 years old), measure their height and weight twice every six months. If a measurement shows a sudden increase in height and weight, it indicates that the girl may have menstrual cramps in the following six months.
2. Observe the condition of the breast: If it is found that the breast begins to develop, swells, and the areola appears, and there is an induration when touched, then menarche will occur within the next two years.
3. See if there is leucorrhea: It is normal if a transparent, colorless, odorless and slightly viscous liquid like egg white flows out of the girl’s vagina; if the leucorrhea is brown, it indicates that menarche is coming 2-3 days later .
4. If pimples appear (pimples on cheeks and forehead, and there are small pustules), menstruation will come within 2 to 3 months.
menstrual cycle
The first day of bleeding is the beginning of the menstrual cycle, and the interval between the first day of two menstrual periods is called the menstrual cycle, so the calculation of the menstrual cycle should include the time of menstrual cramps. Some women only count the time when the menstrual period is clean, so they may think that the menstrual cycle is shortened. In clinical practice, some women often complain that their menstrual cycle is abnormal, and menstrual cramps are twice a month. In fact, after careful calculation, it is normal to have a wave at the beginning of the month and once at the end of the month. The normal menstrual cycle is 28 to 35 days. The length of the cycle can vary from person to person. 7 to 10 days in advance or wrong can be regarded as the normal range. As long as a certain regularity can be maintained, it cannot be considered as irregular menstruation.
The last menstrual period refers to the most recent menstrual period from the date of consultation, which should be calculated from the first day of bleeding. However, it should be noted that the last menstrual period refers to the same duration and amount of menstruation as usual. Do not mistake abnormal vaginal bleeding for menstruation. This kind of bleeding is generally less than menstrual, the time is shorter or longer, or the regularity of menstrual cramps is lost.
The duration of menstrual cramps is generally 3 to 7 days, and the bleeding volume is within 100 ml, with the 2nd to 3rd days being the most. Menstrual blood is generally dark red and does not coagulate. In addition to blood, it also contains endometrial fragments, cervical mucus and vaginal epithelial cells. Generally, women are asymptomatic during menstruation. A few people may experience discomfort in the lower abdomen or lumbosacral region, breast tenderness, constipation or diarrhea, headache and other discomforts, which generally do not affect their daily work, study and life.
menstrual symptoms
Usually there are no special symptoms, but sometimes there may be general malaise, fatigue, breast tenderness, swelling of hands and feet, lower abdomen and back soreness and falling, etc., as well as constipation, diarrhea (prostaglandin effect), frequent urination and anorexia. Individuals have symptoms such as headache, insomnia, palpitations, mental depression or irritability, which mostly disappear after menstruation.
ovulation date
A menstrual cycle refers to regular, periodic bleeding from the uterus. With this bleeding, there should be follicle maturation, ovulation and corpus luteum formation in the ovary, and changes in endometrial hyperplasia and secretion. Ovulation is affected by the endocrine hormones of the pituitary gland and ovary and presents cyclical changes. The length of the two cycles is the same, one cycle per month, and ovulation occurs in the middle of two menstruation. Women's menstrual cycles are long or short, but the interval between the day of ovulation and the start of the next menstrual period is relatively fixed, generally around 14 days. The calculation method is to count from the 1st day of the next menstrual cramp, count down 14 days or subtract 14 days is the ovulation day, and the ovulation day and the 5 days before and 4 days after it are added together as the ovulation period. For example, if a woman's menstrual cycle is 28 days, the first day of this menstrual cramp is on December 2, then the next menstrual cramp will be on December 30 (December 2 plus 28 days), and then from December 30 days minus 14 days, then December 16 is the day of ovulation. The day of ovulation and the 5 days before and 4 days after it, that is, from December 11 to 20, is the ovulation period.
In addition to the menstrual period and the ovulation period, the rest of the menstrual cycle is a safe period, so in the menstrual cycle there is a safe period before ovulation and a safe period after ovulation. In fact, this is also the theoretical basis of the rhythm contraceptive method. However, to use this method to calculate the ovulation period, you must first know the length of the menstrual cycle, in order to calculate the accurate time of the next menstrual cramp, and then to calculate the ovulation period, so this method can only be applied to women whose menstrual cycle has always been normal. For women with irregular menstrual cycles, it is impossible to predict the date of the next menstrual cramp. Therefore, the ovulation day and ovulation period cannot be estimated.
cycle change
One of the physiological characteristics of the female reproductive system is its cyclical changes, and menstruation is an important symbol of this cyclical change. The menstrual cycle is mainly regulated by the interaction between the hypothalamus-pituitary-ovary. The hypothalamus regulates the function of the pituitary gland, which in turn regulates the function of the ovary.
The endometrium undergoes periodic changes under the action of ovarian hormones. The sex hormones produced by the ovaries, in turn, act on the hypothalamus and pituitary gland, affecting the release of gonadotropin-releasing hormone, follicle-stimulating hormone and luteinizing hormone, which is called feedback; inhibiting their release is called negative feedback, prompting their release is called positive feedback.
The relationship between the changes of blood hormones in the normal menstrual cycle and the ovary and endometrium is as follows: after the corpus luteum atrophy in the previous menstrual cycle, the secretion of estrogen and progesterone decreases, and the inhibition of the hypothalamus and pituitary is relieved. The gonadotropin-releasing hormone produced by the hypothalamus enters the anterior pituitary through the pituitary portal system to promote the secretion and release of follicle-stimulating hormone and luteinizing hormone. Under the synergistic effect of follicle-stimulating hormone and luteinizing hormone, the follicles in the ovary gradually develop and mature, and produce estrogen, which causes the proliferative changes in the endometrium. After the follicles mature, there is a first peak of estrogen in the body.
The increase in estrogen secretion has a feedback effect on the hypothalamus and pituitary gland, inhibits the production of follicle-stimulating hormone, promotes the increase in the secretion of luteinizing hormone, and the peak of luteinizing hormone occurs, which triggers ovulation. After ovulation, the corpus luteum forms and secretes estrogen and progesterone. Under their combined action, the endometrium undergoes typical secretory changes. After ovulation, estrogen levels temporarily decrease, followed by a second, lower peak.
A large amount of estrogen and progesterone secreted by the corpus luteum inhibits the hypothalamus and pituitary through negative feedback, so that the secretion of follicle-stimulating hormone and luteinizing hormone is reduced, and the corpus luteum begins to atrophy. After the atrophy of the corpus luteum, the secretion of estrogen and progesterone declines, and the endometrium cannot be supported by sex hormones, resulting in necrosis, shedding, and menstrual cramps. After the atrophy of the corpus luteum, the inhibition of the hypothalamus and pituitary gland is also released, so that the gonadotropin-releasing hormone is secreted again, and another menstrual cycle begins.
Menstrual effects
Many women often lament that they bleed every month after menstruation, which greatly reduces the chance of getting cancer, which is about 40% smaller than that of men. Speeding up your metabolism is good for your body.
pregnancy signal
Married women of childbearing age, the previous menstrual rules, the menstrual period of more than ten days in the future, should first consider whether they are pregnant. After confirmation of pregnancy, those who are not ready to give birth should take remedial measures as soon as possible; those who want to give birth should pay more attention to nutrition, avoid exposure to tobacco, alcohol, pesticides, harmful chemicals, radiation, etc., and avoid taking drugs that can cause fetal malformations. According to the menstrual period, the expected date of delivery can also be estimated, which is very beneficial to the health care during pregnancy and the psychology during pregnancy.
menstrual cycle
disease signal
If the girl is over 18 years old and still has no menstrual cramps, it is called primary amenorrhea; women who have had normal menstruation in the past and are now stopped for more than three months are called secondary amenorrhea (excluding those caused by pregnancy, breastfeeding, and menopause). ), it is necessary to check for lower genital tract atresia, congenital absence of uterus or uterine dysplasia, ovarian tumor, pituitary tumor or hypofunction, endocrine or wasting disease. In addition, changes in menstrual time, volume, and accompanying symptoms are also important clues for the discovery and diagnosis of many diseases.
hematopoietic function
Menstruation causes regular blood loss and hematopoiesis in the body, giving women's circulatory system and hematopoietic system a "training" that men don't have. New blood to make up for lost blood. Practice has proved that men and women with the same weight and health status lose the same proportion of blood due to accidental loss, and men will die because of this, while women have the possibility of successful rescue and eventual recovery.
Reduce iron damage
There is a hereditary disease called hemochromatosis, which can easily lead to disorders of iron metabolism in patients, and excess iron will accumulate in the body; excess iron will slowly lead to lesions in the skin, heart, liver, joints, islets, etc. One of the ways to treat iron overdose is to drain a certain amount of blood on a regular basis. The organic damage caused by hemochromatosis is much less likely to occur in women than in men, or even almost non-existent. The role of menstruation-periodic blood loss just consumes excess iron.
