Although dysmenorrhea is not a serious illness, I have experienced that kind of inexplicable cramping or falling feeling, and I have lingering palpitations.
And the few days when the aunt visited, was also the strongest moment of the girls’ desire to «reincarnate as men in the next life».
They may doubt life more than once, and ask such a heavenly question: Why do humans have to have a menstrual cycle?
It is true that menstruation is a key part of the female reproductive cycle.
Every month, the female endometrium thickens and stratifies, forming an extensive network of blood vessels, waiting for the embryo to implant.
But not every egg can wait for the sperm that belongs to her.
If a woman fails to conceive, the levels of estrogen and progesterone will drop, and the thickened endometrial tissue and blood vessels will fall off.
As a result, what we call menstruation is formed, which will last for 2-7 days with a total of 20-100ml of blood loss.
It can be seen that there is genuine blood flowing here. The energy lost in one menstrual period can cover about 6 days of daily nutrient intake.
Losing so much nutrition in vain every month is already very puzzling.
What’s more deadly is the pain and inconvenience caused by menstruation.
For example, menstruation in the virgin forest may become a clue to be hunted down, or menstruation may be excluded from hunting activities due to menstruation.
Although in addition to humans, other mammals also have reproductive cycles.
But the difference is that most mammals do not have a big aunt (dogs are vaginal bleeding during estrus, not «big aunts»).
The presence or absence of aunt is also a factor that distinguishes advanced primates from other mammals.
So scientists are as puzzled as many female compatriots about how many evolutionary benefits it will bring to humans to evolve such a cumbersome and wasteful regular bleeding procedure.
However, all kinds of hypotheses have been divergent over the years, and they are hard to distinguish.
As early as 1920, the famous paediatrician Béla Schick coined the term «Menstrual» 1920. He believes that menstruation is actually a filthy existence, and toxins will be excreted during menstruation.
At that time, he also conducted an experiment and found that the flowers touched by the hands of menstruating women quickly withered, and claimed that it was caused by «menstrual toxins.»
However, humans have not yet discovered the existence of this toxin, and the hypothesis of stigmatizing women is also self-defeating.
By the end of the 20th century, another diametrically opposed hypothesis was gaining eyeballs, believing that the function of menstruation was to «protect the uterus against pathogens brought by sperm.»
But this hypothesis was quickly overturned due to lack of evidence.
The reason is simple because the menstrual period will increase the risk of infection.
For example, microorganisms grow better in blood rich in iron, protein and sugar, and the mucus around the cervix is also reduced during menstruation, and microorganisms are also more likely to invade.
It has also been suggested that menstruation is to exercise women’s hematopoietic function.
Unlike men, considering that they tend to lose a lot of blood during childbirth, this kind of exercise seems to be necessary for women.
Facts have also proved that men and women with similar physical conditions will lose the same proportion of blood due to accidents, and men will die as a result, while women have the possibility of successful rescue and eventual recovery.
But this hypothesis also cannot withstand careful scrutiny and is less convincing.
Because of the primitive period, women were already mothers as soon as they entered puberty.
This also means that this kind of exercise opportunity is rare, especially for the first child who needs exercise most.
The most reliable one at present comes from Deena Emera of Yale University.
A paper she published in 2011 proposed that menstruation is actually the result of the uterus against the embryo, which depends on the mother’s control of her uterus.
All fetuses go deep into the mother’s uterus to draw nourishment.
However, there will be differences in the degree of depth between species. For example, embryos such as horses and cows are only located on the inner surface of the uterus, while dogs and cats will go a little deeper.
The fetuses of humans and other primates penetrate almost the entire endometrium as if they were bathed in the mother’s blood.
From an intuitive point of view, the monthly thickening of the uterine lining seems to be fertile ground for implanting embryos in order to better implant the embryos.
But in fact, the uterus itself does not want to implant the embryo at all.
After all, once the placenta is successfully implanted, the mother will lose full control of her hormones.
For example, the placenta can produce various hormones and then use the hormones to manipulate the mother’s body, and the baby can also directly and unrestrictedly draw the mother’s blood supply.
A long time ago, scientists tried to transfer embryos to various parts of the mouse body.
In the abdominal cavity, thoracic cavity, and even the back, the embryo is implanted easily.
But what is unbelievable is that the endometrium is the hardest place for embryos to take root.
It is completely an embryo testing ground, and only the most aggressive and strongest embryos can take root.
This shows that the conflict between the uterus and the embryo may be more ferocious than imagined.
Therefore, based on this kind of battle between mother and child, Emera’s team believes that the mother had to do a defensive job before the embryo invades and thicken the endometrium.
Only in this way can we protect ourselves from greedy and selfish embryonic claims.
So why does the thickened endometrium fall off again? The explanation is to get rid of bad embryos.
In the war between the uterus and the embryo, one party will always end in failure.
If the uterus fails, the fetus will continue to take root and grow in the uterus until it matures and is discharged from the body.
But the embryo siege failed, and the matter was not that simple.
If the embryo was still in a free state at that time, it would be fine, and it would not have any big impact.
But if the embryo is half-dead in the womb, it will be troublesome.
It seems that they have been implanted but have not yet formed an umbilical cord connection, or they are too weak to carry out further offensives against the uterus.
Therefore, in order to solve the problem, it is a good choice to peel off the entire surface of the endometrium every month and to exclude the dead embryos from the body.
Before any signs of pregnancy appeared, about 30% to 60% of embryos were unceremoniously discarded in this way.
From the perspective of natural selection in the theory of evolution, this is also self-consistent.
Human embryos are always prone to abnormalities, which is closely related to our unique sexual habits.
Unlike other mammals that can mate only during a specific estrus period, humans can mate at any time throughout the reproductive cycle. There is no such thing as an anestrus period.
This condition is also called «extended copulation«, and other menstrual animals such as bats and elephant shrews (qú) have this phenomenon.
«Extended mating» causes the egg to be fertilized several days after it is formed, which can easily cause abnormal embryos.
If you encounter poor quality embryos, this is a huge waste for the mother who needs to conceive in October.
Imagine that it is obviously not worth taking such a big risk for a weak and unviable fetus.
Therefore, spontaneous shedding and knowing how to stop the loss in time when a bad embryo is identified is the real way to save resources.
In addition, because the human estrus period has disappeared, both men and women can have the sexual desire at any time, making them more entertaining.
Therefore, the number of mating times of humans is far greater than that of any kind of animal.
The chance of a female uterus being invaded by bad embryos will also increase accordingly.
From this point of view, the menstrual mechanism is even more necessary.
To sum up, the existence of menstruation may be to resist the invasion of embryos, or it may be a phenomenon caused by the screening of inferior embryos, or both.
Therefore, for all of us to continue our descendants, we have to thank women for their monthly sufferings.
As for dysmenorrhea, it is a by-product of menstruation, which is also divided into two types: primary dysmenorrhea and secondary dysmenorrhea.
The shedding of the endometrium does lead to direct exposure of blood vessels and bleeding.
But under normal circumstances, the process of automatic shedding itself does not bring any strange feeling, which is a bit similar to peeling.
The primary dysmenorrhea is related to the level of the prostate.
When the eldest aunt visits, the human body will secrete prostaglandin-pgf2α, which can promote the continuous squeezing and contraction of uterine smooth muscle to expel the shed endometrial membrane.
If prostaglandin-pgf2α is too high, it will cause excessive contraction of uterine smooth muscle and vascular spasm.
Dysmenorrhea in this case is also called primary, and there is no qualitative change.
Relative to primary, secondary dysmenorrhea is caused by pelvic organic diseases, such as pelvic infection, endometriosis, and uterine fibroids.
Once this kind of disease appears, it needs to be treated in time, and the right medicine is prescribed.
In fact, in primitive society, due to short life, malnutrition, late puberty and lack of moral restraint, etc.
Our hunter-gatherer ancestors are likely to conceive and have children from the first ovulation and then have been in a state of frequent births.
Therefore, they have not been tortured by their eldest aunt many times in their lives, and the menstrual period may be as few as 50 times.
The Dogon people living in Mali are a typical natural fertility group (without any contraceptive measures). Women in this group only need to experience 100 menstruation in their lifetime.
In the fertile age of a modern woman, an average of about 450 menstruation occurs.
This is actually unusual in the entire civilization process.
But modern society also has the benefits of modern society.
Based on science and technology, women actually have the right to choose not to suffer from menstruation.
Everyone must have heard of the miraculous existence of short-acting contraceptives.
In 1957, the US Food and Drug Administration approved short-acting contraceptives for the first time.
We all know that women who are not troubled by menstruation in their lives are only pregnant in October (or after menopause).
The principle of short-acting contraceptives is to simulate the state of pregnancy so that the body always maintains a certain amount of estrogen and progesterone levels.
In this way, the body will think that it is in a pregnant state and will no longer order the ovaries to ovulate.
Back then, female doctors and nurses in the United States took the lead in choosing to abandon menstruation. After taking the third week of pills, they immediately started taking the next drug.
By the beginning of the 21st century, various pharmaceutical companies have also introduced tablets that can be taken continuously.
Some pills can be taken continuously for 12 weeks; some only bleed once every three months; some can prevent women from having menstruation within a year, etc., and the maintenance time is getting longer and longer.
Just suppressing menstruation is relatively short in medical history.
Although it is currently believed that long-term short-acting oral contraceptives can reduce the incidence of ovarian cancer and endometrial cancer. However, facing the big aunts who have been with them but suddenly disappeared, the female compatriots still find it difficult to overcome the psychological barriers.
But at least, modern women can still hold control of the body in their hands.
*Reference material Shreya Dasgupta.Why do women have periods when most animals don't?.2015.04.20 Suzanne Sadedin.Why do women have periods? What is the evolutionary benefit or purpose of having periods? Why can’t women just get pregnant without the menstrual cycle?.Quora.2014 Andrew M. Blanks ,Jan J. Brosens.Meaningful menstruation:Cyclic renewal of the endometrium is key to reproductive success.BioEssays.2013.04.12 Stephanie Buck.The inventors of the Pill decided women should still bleed every month.Timeline.2017.05.03