Children born from one pregnancy. Fraternal twins are distinguished - developed from different zygotes, and identical twins - developed from one zygote, which then divided into two or more embions. Identical twins are very similar to each other.
Twins, monozygotic and dizygotic, make up approximately 1.5% of the population of our planet. This is more than a hundred million people on Earth, in terms of number - like the inhabitants of, for example, two Frances. What affects the appearance of twins, who are called Siamese twins, and who are twins, is it possible to predict the birth of twins, and what are the features of bearing and raising such children, MedAboutMe tells.
Although there are two different words in Russian - “twins” and “twins”, which refer to children born from the same mother at the same time, these concepts are often confused. Their correct use implies that twins are children born as a result of the division of one egg. Such babies are almost identical in terms of gene set, and are almost one hundred percent copy of each other, although sometimes there are minor differences.
Twins are dizygotic, multi-ovarian twins, children who appeared as a result of the presence of two or more eggs in the mother, which are fertilized and gestated during one pregnancy. However, these babies, although similar to each other, are not identical twins. They have a partially different set of genes and are considered as close as siblings, brothers and sisters born at different times from the same.
The average twin birth rate in the population is 1% and has been on the rise in recent years. Slightly less than a third of this number are identical twins, the rest are twins (triplets, etc.). The number of identical twins in nature is invariable and does not depend on external factors, but the conception and successful bearing of twins is influenced by both changing socio-economic conditions and the development of medicine and pharmacology.
In addition to identical and multiple twins, there is a separate, intermediate type: homozygous polar twins, also called semi-identical. Such children are born extremely rarely due to the complex specific process of splitting the polar body, the part of the egg that usually dies before fertilization. In some cases, the polar body, which has the same chromosome set as the egg, begins to divide and grow, and can be fertilized by a sperm. In this case, babies are born in which the maternal part of the genes is completely the same, but the set from the father is different. This intermediate type combines the characteristics of monozygotic and dizygotic twins. Children in such couples can be born, for example, with the same appearance, but at the same time be of different sexes.
Identical twins are called monozygous or homozygous. After the egg is fertilized by the sperm, a zygote is formed. In the process of development, it can be divided into two or more parts, and it is in this case that twins have the opportunity to be born.
From the time of crushing the zygote depends on how the pregnancy will proceed. The most common case is the crushing of the zygote on the 6th day after union with the spermatozoon. The later the separation occurs, the higher the possibility of developing twins in the same amniotic sac. So, when crushing for up to 3 days after conception, children will develop in separate bubbles and eat from their “own” placentas, when separated from 4 to 8 days, each fetus will have its own fetal bladder, but one placenta will form. The period of separation from 8 to 13 days means that they will mature in one bladder with blood supply from one placenta.
Later terms of separation of the zygote in most cases lead to such a phenomenon as Siamese, or conjoined twins.
Later (after 14 days from the formation of the zygote), the separation of the fertilized egg provokes the formation of Siamese twins. By this time, some organs are already beginning to form, and the zygote is not completely crushed, which leads to the impossibility of complete separation and the development of two independent embryos.
The frequency of this phenomenon is not precisely defined, since some of the embryos do not survive, approximately 50% of pregnancies end in stillbirth. Statistical data: the birth of living Siamese twins ends 1 pregnancy out of 200,000.
However, even after birth, such children have far from one hundred percent chances of survival. Depending on the degree of union and the availability of medical care, Siamese twins have the opportunity to grow and develop in 5-25%. More often (up to 3 out of 4 cases) girls are born.
The very name "Siamese twins" was fixed after a long tour of the famous couple Chang and Ang Bunker together with the Barnum Circus. The Bunker twins were born in Thailand, which at the beginning of the 19th century was called the country of Siam. The pathology of the fusion of this pair is called xifopagia (fusion of the cartilaginous tissue of the chest), in the conditions of modern medicine, such cases are quite easily corrected, and Siamese twins have the possibility of a separate existence. The following fact testifies to the degree of influence of xipophagy on the body of twins: Bunkers lived for 63 years, were married to two sisters and had healthy children (according to some sources, the brothers had 21 children). However, the death of one twin of the pair from pneumonia led to the rapid death of the second due to intoxication. Later it was found that the brothers also had a fused liver.
Other options for pathology include:
- omphalopagia. Omphalopagus twins occur in 34% of cases; with this type of fusion, they most often have common digestive and hematopoietic organs, the lower part of the chest is united;
- Thoracopagia, of which the Bunker xifopagi twins are a special case, is a fusion of the chest. This is the most common case (up to 40%). Most often, the presence of a single heart is noted, with such a phenomenon, the chances of survival for twins are extremely low, separation of bodies is impossible;
- oropagia, 19%. Fusion occurs in the buttocks, back, iliac region of the body;
- craniopagia, 2%. The fusion is necessarily present in the region of the skulls, depending on the fusion of the bodies, it can be divided into several subspecies of the pathology. Extremely low chance of survival. The birth of such children in ancient times served as reasons for the emergence of legends. In particular, the legend of the two-faced god Janus could have been provoked by the appearance of cephalopagic children fused with their heads;
- polycephaly: on one body - two (in rare cases three) heads and two or more arms;
- etc., depending on the area and degree of union.
The most famous twin sisters
In Russia, the most famous twin sisters were Masha and Dasha Krivoshlyapov and Zita and Gita Rezakhanov. Both pairs belong to ischiopagus biznets, with an anterior type of connection of body parts and fused spines.
The Rezakhanov twin sisters were successfully separated surgical method at 11 years old. Zita lived for 24 years and died due to multiple organ failure in 2015.
The twin sisters Krivoshlyapovs lived for 53 years (1950-2003). Masha's death from a heart attack led to the death of Dasha, as a result of intoxication of the body through the common circulatory system.
The most famous stories are cases of the appearance of unusual, Siamese twins. Aside from legends, the first reliable mention of such children dates back to 179 AD, recording the appearance in China of a craniophage, a two-headed child. At various times, many conjoined twins have attracted public attention and left their mark on history. Some of the testimonies refer only to medical facts, some tell of amazing people with a single body, becoming famous, usually performing in circuses or music salons.
The first known mention of an attempt to separate Siamese twins belongs to Byzantine doctors: an adult pair of brothers was tried to be separated from each other after the death of one of them. Unfortunately, the surviving twin lived only 3 days after the operation.
The birth of identical children, identical twins, has led to the emergence of a number of myths. For example, the myth of telepathy among twins is quite stable, and is based on high empathy, understanding of each other's reactions to certain events, associated both with the features of joint development and with the matching reactions of the psyche of similar children.
The myth of a 100% match, the complete identity of twins, is incorrect. Although in monozygotic children, the DNA chains coincide by 99.99999%, but this is not an absolute identity. Moreover, about a quarter of identical twins are called "mirror": they may have moles located on different sides of the body, as in mirror reflection, one of a pair of children may have internal organs With opposite side. Often in a pair of twin children, one is born right-handed, and the second is left-handed.
True claims include the ability of animals to distinguish between twins by smell. Even children, who are sometimes difficult to distinguish between parents, smell differently for animals, despite the same living conditions, diet, activity and health status.
But the fingerprints of homozygous twins differ, although not completely: the formation of skin patterns on the pads is influenced not only by the gene sequence, but also by touching the umbilical cord and skin during fetal development.
The development of other myths about twins, such as the ability to inherit the probability of the appearance of such children in the family, or the possibility of having a boy and a girl in a pair of twins, led to the confusion of the concepts of "twins" and "twins". This type of myth is true only for dizygotic children developing from different eggs.
Two twins or more? How many twins can there be
Two twins or a pair of twins is the most common option. However, three, four or more children can be born. To date, the maximum number of viable children born as a result of multiple pregnancy is 9 babies.
At the same time, among the babies born, there can be monozygotic, dizygotic children, or even a “mixed composition”: for example, in triplets there can be two twins and one child that developed from a separate egg.
Polar semi-identical twins are still a little-studied phenomenon, but at the moment the prevailing opinion is that there can be no more than two of them.
For many millennia, people have tried to understand what leads to the birth of twin children, and what marks the birth of several children at once, especially if the babies were born exactly the same or fused.
In some countries, the birth of twin children was considered a sign of good luck and happiness in the family, in other nations it was a harbinger of wars and troubles.
In attempts to avoid or stimulate the birth of twin children, various signs appeared. So, eating “double”, deformed fruits, berries with two seeds instead of one, bananas with one bunch was considered one of the ways to help conceive and give birth to two or more children at once.
Some of the signs are confirmed by science: the ability to give birth to twin children is indeed inherited if different eggs are fertilized. The influence of a non-standard type of fruit on the birth of twin children has not been confirmed, but there are a number of factors that increase the likelihood of multiple pregnancies.
The birth of monozygotic and semi-identical twins cannot be controlled, the process of the appearance of identical children cannot be predicted or stimulated, it is not due to a genetic predisposition and cannot be analyzed.
Identical twin children are born on average in 3 cases out of 1000, that is, the incidence of zygote division and pregnancy is 0.3%. But the conception of multi-egg twins has several characteristics that allow you to predict the probabilities and even control the process.
Natural pregnancies, accompanied by the fertilization of 2 or more eggs, occur about 5 times more often. In vitro fertilization, when several eggs are planted in the uterus, in many cases leads to the appearance of dizygotic twins.
Twin children, born as a result of the division of one egg, can appear in any family. But the birth of twins is influenced by several established factors.
Statistically reliable fact that twin children are born most often in women from Nigeria, constituting indigenous people country. Also, couples whose close relatives had a history of conception or the birth of twins have a high chance of giving birth to twin children.
Twin babies are also more likely to occur in mothers over the age of 35, women who have undergone egg-stimulating therapy, and those whose pregnancy begins after stopping birth control, as this causes an increased activity of the ovaries in the production of eggs.
When two or more eggs are planted in the body of a future mother, it also leads to the appearance of twins with a high frequency if the embryos take root and the parents decide to bear them. This practice has led to some increase in the number of dizygotic twins in recent decades.
There are some factors that can affect the birth of twin children, developed as a result of the fertilization of two or more eggs. It is impossible to control the conception of identical twins, however, if you want to give birth or avoid the birth of dizygotic children, you can talk about some confirmed facts that indicate the presence of the influence of diet, age, heredity, etc. on the appearance of multi-egg twins.
Natural factors that affect the ability to give birth to twin children include:
- heredity, genetic predisposition to the maturation of several eggs in one cycle;
- genetic propensity identified in some nationalities;
- mother's age. At 18, the average probability for a woman to give birth to twin children is 0.27%, at 35 - 1.47%, then the chances decrease;
- number of pregnancies and births. During the second pregnancy, the chances of giving birth to twin children increase by 2 times, after 3 - by 5. If a woman has already had twins, then the chances of repeating the birth of twin children are multiplied by another 2;
- strict diets reduce the likelihood of twins, and a long daylight hours during ovulation - increases;
- some foods that, according to research, can provoke the simultaneous release of mature eggs from the ovaries, such as yams or sweet potatoes, a natural source of a hormone-like substance.
Medical types of stimulation of egg maturation include special preparations commonly used in infertility therapy. Such measures are possible if you want to conceive and give birth to twin children, but are not recommended.
The effect of the withdrawal of long-term use of hormonal contraceptives often leads to the active work of both ovaries, which can provoke the maturation of two eggs at the same time in the first two cycles after stopping the use of medications.
In vitro fertilization, in which more than one zygote is implanted in the uterus, also makes it possible to give birth to twin children.
Recently, statisticians have been talking about the influence of environmental factors, stress, changes in the diet that affect the body of women and lead to both difficulties with conception and an increase in the number of twins born due to the unstable work of the reproductive system.
Children of twin parents who are dizygotic have an increased chance of conceiving and having twins. Children of twin parents born as a result of the separation of one zygote, according to statistics, do not inherit this property.
An example, however, is the story of two families in which identical male twins are married to identical twin sisters. (This situation is not non-standard: it is statistically confirmed that twins and same-sex twins, due to the peculiarities of mental development, often form families with members of the same pairs of twins.)
Craig and Mark Sanders and Diana and Darling Nettermeyer gave birth to five children, and one pair had identical twin boys, and the second had three children in turn: two daughters and a son, which indirectly indicates a possible, but not yet studied, probability of inheritance of certain factors leading to division of the zygote.
Studies confirm that the probability of having identical twins in a couple where the parents were also born due to zygote splitting is almost 1 chance in 1,000,000.
A more complete study is hindered by statistics: the occurrence of such pairs for the possibility of studying them is extremely low.
Carrying and giving birth to twins: features
The bearing of a multiple pregnancy proceeds with its own characteristics. As a rule, mothers of future twins or twins are more tired, more likely to encounter manifestations of toxicosis, preeclampsia, and a higher risk of miscarriage.
The birth of twins in half of the cases is carried out operational method caesarean section. This fact is mainly due to the stretching of the uterus during multiple pregnancy, which leads to weakness of labor, as well as the peculiarities of the location of the children, preventing passage through the natural birth canal.
In the absence of contraindications, the birth of twins naturally occurs in the maternity ward of ordinary maternity hospitals. As a result of multiple pregnancies, babies are usually born underweight (up to 3 kg).
Contrary to popular belief, identical homozygous twins can be born with a different shade of skin, and even have differences in body weight up to 300 g.
Twin children in the family require not only simultaneous attention to physiological needs, but also a special approach. Babies born at the same time get used to being together, sharing each other's interests, which leads to complications in separation, separation, as well as specific problems in the formation of the personalities of twin children.
This applies least of all to pairs of opposite-sex twins, most of all to pairs of identical twins.
For identical children, experts advise not only to try to allocate separate time for each child, but also to stimulate the development of their own interests and preferences that do not match in a pair. What they usually try to teach siblings with an age difference - to live together - turns out to be the exact opposite goal when it comes to twin children, especially identical ones. Such kids need to be taught to live separately, not to close on each other, to eradicate the lack of social ties and communication with other children.
One of the features of twin children in families is cryptophasia, a specific language made up of deformed words (onomotapeia), thanks to which children understand each other better. A similar phenomenon, very common among twins, can make it difficult, slow down the development of speech skills, and cause a lag in language development.
For example, psychologist Rene Zazzo, who studied pairs of twin children in a family, proved that in most cases, the twins reach the mastery of speech skills of the norm of 4-5 year old children only by the age of 6-7 years, subject to socially and economically prosperous living conditions.
Various features accompanying the development of twin children should attract the attention and efforts of parents aimed at identifying, emphasizing specific features, striving to enable and motivate children to form as separate individuals. Psychologists advise to send babies from the age of 10-12 months to various games and activities, dress differently, cut their hair, give different gifts, take them to Kindergarten on different days, write them down in sections separately, if possible, separate them at school, and also do not call the kids to you “Children, go to dinner”, but address everyone by name.
Otherwise, children born together have a fairly high chance of living their whole lives without making a new couple, but being dependent on each other. Statistical studies show that twins (as well as same-sex twins) are much less likely to marry and form families. Most often this happens in the absence of the possibility of the process of individualization of the child during the period of active mental development.
If there are triplets in the family, a couple is most often formed, the third child is not included in the tandem and grows like a sibling of the same age. If there are four twin children, two stable pairs are formed, and so on.
In pairs of twins, in most cases, a “slave-leader” relationship is established, and factors other than those in pairs of girls or opposite-sex tandems become the basis for determining the leader. Twin boys tend to form a dominance and submission pattern in 80% of twin pairs and 75% of identical twin pairs.
Relations of dominance over a brother in twin boys develop in early childhood, as a rule, a more physically strong baby becomes the leader in a pair, the one who develops better, eats, moves more actively, or the one who, by right of birth, is the first, parents call the firstborn or emphasize it in conversation with children.
During life, roles in a couple can change, although this does not happen so often. Twin boys can change the balance of dominance in adolescence or share leading roles: someone becomes a leader in studies, a second more developed athlete, etc.
In pairs of heterozygous twins of different sexes, in most cases, girls dominate at the initial stage (66% of couples) due to earlier social development, while the physical characteristics and IQ of children may coincide, but do not affect the dominant position.
twin girls
Twin girls also tend to form master-slave pairs. However, unlike males, female twins, when choosing a dominant sister, rarely focus on physical characteristics, preferring social components: success at school, in a company, and intellectual advantage.
In the established system of horoscopes, there are different years and periods that promise people born in this period of time special, different signs, preferences, twists of fate, dictating specific requirements for lifestyle, choice of partner, profession, etc.
Data folk beliefs partly based on observations of people whose intrauterine period occurred, for example, in the winter-spring period, not rich in sunlight and vitamins, and infancy passed under the active rays of the sun and in light diapers, with frequent walks, and the diet of the nursing mother was enriched fresh vegetables and fruits, or vice versa.
Some general coincidences in the pace of physical and mental development of people born in the same period of time can be found in various horoscopes and predictions, but this method cannot be called scientific.
If we talk about the concept of "children of the year twins", then this is the wrong wording. Gemini is a sign corresponding to the time period from May 22 to June 21, but not a one-year interval.
Of course, the birth of a child is a great joy for parents. What if there are two kids? Then the joy is twice as much. Therefore, if you really want to give birth to two children at a time, then you should be aware of some of the factors that contribute to this.
Almost half of women really want to be able to give birth to two babies at once. They believe that it will be much more comfortable for children to grow up together, and it will also be much easier to raise them together. In addition, in this case, you can give birth only once, and there will be joy, as if for two times! But how can this be influenced? After all, statistics show that there are not so many cases of the birth of twins. For example, out of 80 women, only one can give her family two children at once.
What are the differences between twins and twins?
Very often women cannot answer this simple question. Twins are fraternal children, and twins are identical. For twins to be born, two sperm need to fertilize two eggs at the same time. In this case, each of the children will have their own personal placenta. Also very interesting fact there is the fact that such children can be of different sexes and be either very similar to each other or be very different. The ability to give birth to two children can be transmitted exclusively through the mother. In addition, the birth of twins is much more common. than the birth of twins.In what case can twins be born?
Of course, you can choose a person from Africa or the Middle East as your soulmate. After all, it is in these countries that the birth of twins is far from uncommon. But do not reject heredity, because it also plays a big role. If there are and were twins in your husband's family, then the chance of giving birth to twins is quite large. It is also known that the birth of twins is genetically laid and passed down through the generation.Age and twins
Scientists have proven that it is most often and easiest to conceive and give birth to twins for a woman aged 35 to 38 years. But why is this happening? It's no secret to anyone that during menstrual cycle Only one egg can mature in a woman's body. And only when the level of the hormone is significantly elevated. And the higher this level of the hormone, the more eggs can mature. And therefore, it is at this age that a woman's level of necessary hormones is much higher, which means that the chance of having a multiple pregnancy also increases significantly.Also an interesting fact is that twins are most often given birth by a woman who already has children. And the more pregnancies you had, the more likely you are to have twins. Some scientists argue that an important point in the birth of twins is the long-term abstinence of both partners. If this is done, then the man will produce much more sperm.
Experience of India and Transcarpathia
V Transcarpathian region there is one amazing village - Velyka Kopan. As you know, 54 pairs of twins were born there in 50 years. Some may think that this is unrealistic, but in fact, everything is simple. The secret lies in the healing spring that the villagers talk about.In India, a village is also known where 70 pairs of twins were born in a short period of time. But the Indians explain this by the fact that their god Rama also had twin children.
Ecorods - 100% twins
If you intend to give birth exclusively to twins, then in vitro fertilization will come to your aid. In this case, the woman is implanted with two or more fertilized eggs. But it is possible that in this case there may not be twins, but even triplets.In some nations, the birth of twins was once considered an omen of happiness and good luck, in others, on the contrary, the result of tricks evil spirits. Now science already knows exactly what is the reason for their appearance. But is it possible to know in advance what is your personal chance of giving birth to twins? What does it depend on? And is it possible to somehow increase or decrease your chances?
Why is this happening?
Let's start with the main thing - why, after all, a woman is born not one child, but several at the same time?
Actually, the very mechanism of this phenomenon, scientists have explained for quite a long time. As you know, a child is born from the fusion of the mother's egg and father's sperm. In a woman, during one menstrual cycle, usually only one egg matures and, accordingly, one child is born. In order to get fraternal twins, it is necessary that two eggs mature and fertilize at the same time. Under the influence of some factors that you will learn about today, sometimes this is exactly what happens.
There is a second case, when one egg, fertilized in the usual way, on the very early stage its fragmentation is divided into two separate organisms with absolutely identical genetic material. As a result, identical twins are born, similar to each other like two drops of water. The reasons for the development of this process by science have not yet been precisely established due to the complexity of the biochemical mechanisms that regulate cell division.
Main "Risk Factors"
Even in ancient times, in an effort to unravel the mystery of the appearance of twins, people came up with many signs that, in their opinion, forced a woman to give birth to not one child, but two or even more at the same time. With the development of science, fully confirmed data have appeared that the greatest role in the occurrence of multiple pregnancy is played by heredity, the age of the expectant mother and her nationality. In addition, it matters what kind of pregnancy it is, whether the woman took contraceptives or other hormonal preparations, and even how she eats, and at what time of the year the conception occurred. Much less frequently, among the causes of this phenomenon, the state of the environment, prolonged sexual abstinence, anomalies in the development of the uterus (bisection of the uterus) and, finally, the social status of a woman (it is estimated that the lower social classes for some reason, twins are born more often).
However, note that all of these factors reduce or increase the chance of having only fraternal twins! The probability of the birth of identical ones is in no way connected with any hereditary and external factors and is constant - on average 3 per 1000 pregnancies, that is, 0.3%.
And, finally, recently the increase in the number of fraternal twins is associated with the widespread use of the technology of "in vitro fertilization" (in vitro fertilization - IVF), when several eggs are fertilized at once for reliability.
Heredity
This is the most proven or significant factor that increases the chances of having twins. Women are most likely to have this predisposition, mainly along the female line (although recent studies show that it is also male, but to a lesser extent). Of great importance is the combination of the genes of both partners (homogeneity of their composition) and patterns of inheritance, which are observed after a generation or two, and most often, in the side branches of the genus (inheritance cousins and sisters). This means that twins are more common in families where the mother or father, or both parents, have twin siblings. The probability of recurrence of twins increases through the generation, that is, if a grandmother had twins at one time, then her granddaughter also increases the likelihood of a recurrence of a multiple pregnancy. In general, the frequency of twins is two to three times higher in relatives of twins than in other people. So if you yourself are a twin, your chance of having a multiple pregnancy is 6%. An even higher chance is if your maternal grandmother had twins. But all this applies only to cases of the birth of fraternal twins. At the birth of identical ones, even among the closest relatives, this will not affect your chances in any way.
Woman's age
Another scientifically proven factor that increases the likelihood of having twins is the woman's age. You can usually read that the older future mom the more likely she is to have twins. However, everything is not so simple here. Very young mothers around the age of 18 really have minimal chances. They have only a 0.27% chance of having twins. But by the age of 25, the probability of this becomes more than 2 times greater (0.62%). At the age of 30, your initial chance will increase by 3 times and will be 0.90%. This figure will reach its maximum by the age of 35, having increased by as much as 5.5 times (1.48%). By the age of forty, the probability of giving birth to twins in a woman begins to decrease again (at 40 years old - up to 1.25%, at 45 - up to 0.73%). By the end of the childbearing period (about 48 years old), the chances of having twins are almost equal to those of an 18-year-old girl (0.30%).
The relationship between a woman's age and the chance of having twins is explained by the fact that over time, the release of an egg (ovulation) in a woman does not occur in every cycle - this is normal. As a result, unrealized hormones that affect ovulation accumulate and are released during the next cycle, stimulating the release of several eggs.
Repeated births
With each subsequent birth, the chances of giving birth to twins increase (after the second birth - two times, after the fifth - five times. If the mother has already had fraternal twins, then the probability of repeating success doubles. Last fact due to the fact that the body of a woman who once conceived twins is able to produce several eggs during the period of ovulation.
Nationality
This is still a little-studied phenomenon, but the fact remains: depending on the nationality of a woman, her chance to give birth to twins can vary by more than 10 times. That is, if you are a resident of Nigeria, then the chances of giving birth to not one, but several babies at once, you have more than 10 times more than, for example, a Chinese woman. When it comes to race, black women are the most likely to have twins, followed by white women, and Asian women at the bottom of the list. But even here it is not so simple. For example, in the same Nigeria (especially in the west), the percentage of twin births is a record high - 4.5%. That is, it means that about 10% of all newborns here are from multiple pregnancies. Although, on average, African women give birth to twins several times less often. But black American women have only a 1.7% chance of having twins. For European women, on average, this figure is 1.4% (while in Norway, Denmark and the Netherlands it is slightly more, and in England - slightly less). Asian women have an average chance of 0.8%, while Chinese women have only 0.4%. What explains this difference is still difficult to explain.
Nutrition
With this factor, everything is also not too clear. It is only firmly known that malnutrition or very strict diets reduce the frequency of twins. Everything else is still in the realm of conjecture.
In general, people have been trying for a very long time to connect the chances of having twins with a woman's diet. For example, in New Guinea, it was believed that if a woman ate two bananas growing from the same head, she would give birth to twins. The Guarani Indians South America it was thought that a woman would give birth to twins if she ate a double grain of millet.
Scientists have received more scientifically confirmed data by studying the diet of the Yoruba people in Nigeria - the champions in the number of twins. Recent research suggests that the birth of the twins is probably due to a local variety of yams. This vegetable, a Yoruba staple, contains a high concentration of the substance, chemical composition similar to the female hormone estrogen, which can stimulate the production of other hormones - gonadotropins. Together, the action of these substances seems to promote the release of more than one egg from the ovary. By the way, those representatives of this nationality who exclude yams from their diet have fewer twins. Although the mechanism of action of hormones is not yet fully understood, there is indirect evidence that they affect the conception of twins. So, if you want twins, go to Nigeria for yams!
Conception time
It is known that the production of the hormone gonadotropin, which stimulates the ovary, is influenced by the length of daylight hours. And therefore (and this is confirmed by statistics) it is more likely to conceive twins in the spring, when the sun begins to noticeably warm up and the activity of sex hormones increases. By the way, for example, in Finland, the highest frequency of double fertilization occurs in July (in the summer in Finland there are white nights, that is, it is light for 24 hours), and the lowest in January (the time of the polar night).
Taking contraceptives
It has been absolutely proven that a woman is more likely to give birth to twins if she becomes pregnant soon after she stops using birth control pills(which took at least 6 months). At the same time, the same gonadotropin, a hormone that stimulates ovulation, is produced in large quantities. Research conducted at Yale University showed that women who used contraceptives and became pregnant within two months of not using them were twice as likely to have twins as others.
Taking other hormonal drugs
The likelihood of multiple pregnancy is higher with special hormonal treatment. For example, during the stimulation of ovulation in the treatment of infertility (anuovulatory disease), when a woman is prescribed special drugs that stimulate the growth of the egg, rupture of the follicle, etc. In such a situation, the body seems to wake up and can “give out” several eggs at once. Of course, it all depends on a single dose of the drug.
But we warn you that it is extremely dangerous to stimulate this process yourself! Firstly, with an overdose (hyperstimulation), ovarian cysts and bleeding often occur. Only a specialist should select the drug, prescribe the dose and control the treatment process. Secondly, if a woman does not yet know about pregnancy and decides to take these drugs on her own, without consulting a doctor, she puts an already conceived child at great risk, since in this case the effect of such medications may further affect his sexual development. In addition, in an absolutely healthy woman, these drugs can cause a sharp increase in the ovaries, their soreness, fever, development and rupture of the cyst.
Artificial insemination
Successfully developing technologies of "in vitro conception" (in vitro fertilization - IVF) also led to the fact that triplets or even "quadruple" pregnancy is no longer a rarity - after all, several fertilized eggs are transplanted into the uterus at once in the hope that one will develop successfully. two fruits. If more than three fruits take root, then the quantity comes at the expense of quality - after all, such children may turn out to be weakened or even unviable. Twins after IVF are always fraternal, often heterosexual, each with its own character.
Brief conclusions
To summarize a little, you can imagine a situation in which you will have the greatest and least chances of giving birth to twins. This is most likely in a 35-year-old Nigerian woman giving birth not for the first time, who previously took contraceptives, regularly ate yams, conceived a child during the white nights, and whose maternal grandmother already had twins. As you can imagine, this is a joke!
But seriously, what are your chances of having twins, only a geneticist can predict. To do this, you need to draw up a pedigree from at least the fourth generation in a straight line and the line of cousins, as well as undergo an appropriate examination. This service is very real and is provided by most major family planning centers.
So, now you know what factors contribute to the birth of twins. But how often does this happen? How many twins live on our planet? Is it true that identical twins share the same soul? And can fraternal twins really have different fathers? You will find answers to these and many other questions in this article.
fraternal twins
As you already learned from the first part of the article, fraternal twins are born when a woman produces not one, but several eggs during one cycle, which are then fertilized. Then these fertilized cells, as they are supposed to, divide, enter the uterus, and there each fetus develops independently. Such twins are, in fact, just ordinary brothers and sisters, only born at the same time. Fraternal twins can be same-sex or different-sex. Their blood type may be the same or different. In general, they have no more in common than between just brothers and sisters. Often they are completely different from each other, have completely different interests and abilities. They are connected only by a common date of birth.
And one more interesting fact about fraternal twins: no matter how fantastic this assumption sounds, they can have different fathers! Although it is believed that both twins are conceived at the same time, there are exceptions to every rule. Although this happens, of course, very, very rarely. This phenomenon is called superfertilization (superfoecundatio). Scientists define it as the fertilization of two or more simultaneously ovulated eggs with sperm. different men and find more and more confirmation of this rare phenomenon.
I must say that the reasons for the birth of fraternal twins have been studied quite well, although there are still some mysteries here. However, there are many factors that were discussed in the first part of this article that affect the birth of such babies. By the way, a noticeable increase in the number of born twins, which has been outlined in recent decades, owes its appearance to fraternal brothers and sisters. This is mainly due to the popularity of IVF (in vitro fertilization, that is, the appearance of “test-tube babies”), since in this case not one, but several eggs are often fertilized.
identical twins
But the birth of identical twins is still surrounded by very big mysteries. How does it happen? The conception scheme is quite standard: one egg plus one sperm. But soon after the usual sacrament, another, completely mysterious thing happens: the embryo, which has already passed certain stages of formation, suddenly splits into two absolutely identical halves. Why such a splitting occurs, no one can yet explain. This is the mystery of the birth of two lives.
If the splitting happened in the first five days after conception, then the development of both fetuses occurs in the same way as it occurs in fraternal twins - each has its own placenta, etc. Such twins, although very similar to each other, can still be distinguished can. But if the splitting occurred on the fifth - seventh day, then the placenta for two is one and the similarity in children will be complete.
As you already know from the first part of the article, unlike fraternal twins, the appearance of identical twins is not associated with any hereditary or other factors. It is always constant and is 3 per 1000 pregnancies, that is, 0.3%
Identical twins can be safely called copies of the same person. They have one gender. Identical twins have the same appearance, the same hair, their shape, texture, hair pattern and color, the same color of the eyes and skin, the shape of the eyebrows, nose and lips, the same pattern of the iris, the shape of the ear, the morphology of the teeth, the similar weight and height, and even similar encephalograms ... In 97% mental qualities match, 92% have fingerprints.
Dogs cannot smell the twins. They even have a surprisingly similar course of diseases, which also appear at the same time.
In general, identical twins are an amazing phenomenon. Since they are created from the same "material", but only divided in half, they must be absolutely identical to each other. Everything that distinguishes them from each other is a consequence of differences in the conditions of maturation, the process of birth and later life.
A lot of almost unbelievable things are told about twins. The story of American twins adopted in infancy by different families is widely known. The brothers had different surnames, and they did not know about the existence of each other. By chance, they were called by the same name - Jailey. Each was married twice, with the first wife of both named Linda, the second - Betty. The twins had the same job. The sons of both were called by the same name. And even the dogs had the same nicknames. All this seems like a fairy tale, but here a certain pattern was most surprisingly identified: often twins appear in life as one person.
Theory of the common soul
I must say that everything connected with identical twins has always been covered with some kind of mystical secret. Many scientific theories, sometimes quite exotic, were created around them. In this article, I want to introduce you to one of them. Perhaps you, like me, will find it interesting.
Today, some light on the phenomenon of identical twins seems to be shed by Moscow researchers studying the human genome. We are talking about the sensational results that they received in the course of many years of experiments. So, it turned out that a huge part of hereditary information is stored not in the genes themselves, but in the wave part of the genome, that is, in the form of a certain energy-information field. And DNA molecules, chromosomes and proteins are a kind of transmitting and receiving devices associated with this field. It is these amazing properties of DNA that ensure the exchange of genetic information in the body and allow each biological cell to instantly recognize what is happening in any corner of our body. DNA is also responsible for receiving information from the outside.
But we are especially interested in the wave part of the genome - a structure that has enormous information capabilities. In fact, this is the very soul of man, about which religion has been talking for more than one millennium. It is to this wave information structure that our DNA molecules are tuned. It is from her that they receive a program for the development of the body. It is in it that our mental individuality, behavioral characteristics, previous experience, and possibly fate options are encoded.
Ordinary fraternal twins are born in different eggs, and therefore they are completely different people. Indeed, in each fertilized cell, random law there is its own combination of genes, its own individual ratio of paternal and maternal information. We can say that their DNA is "tuned" to different souls. This happens because at one time each soul, having connected to a fertilized egg, formed in it a unique combination of genes, which is called “for itself”. In other words, it “tuned” the DNA molecules to their “frequencies”.
Identical twins developed by dividing from one egg. That's where the treasure for science! After all, they duplicated almost the same set of chromosomes. So, they are “tuned” to the same “frequencies”. In other words, per soul. It is possible that it is precisely this "tuning" that explains the striking coincidences in their lives. After all, such twins carry out identical life programs: they have one “control center”, one soul! Today, this view is held by a number of scholars. They directly say that identical twins are elements of a single spiritual and material organism - a holon. And that the synchronism of their actions is caused precisely by this single “control system” (soul).
Why does Nature create twins? Why does she need such duplication? Isn't the reason that, despite all the similarities, each of the twins has their own perception of the world: one has a left (logical), the other has a right (emotional)? And isn't this another strange regularity - the "mirror" of characters? Very often, with an amazing external resemblance, the twins have almost opposite characters. "Volumetric" perception of the world? Why not. It is possible that a single soul, with the help of a pair of “mirror understudies”, perceives the world more fully, and therefore evolves faster. Why don't all souls get twins? Who knows. Maybe twins are needed only for souls who, for some reason, lagged behind, “out of schedule” of their evolution? And perhaps, and vice versa - by the fact that they complete their evolution on Earth, but almost did not get the necessary qualities ...
Curious facts about twins
How often are twins born?
It is statistically reliably recorded that for every 85-90 births there are one twin births, and among twin births, exactly one third is the birth of identical twins. For every 130 twin births, there is one triplet; for every two million normal births, one quadruple. For every 10 million births, there are only Siamese twins.
How many twins are there on earth?
According to various estimates, today in the world there are from 70 to 80 million pairs of twins.
The number of twins born in relation to the total number of newborns in different countries and on different continents it is different, but in general the trend is such that it continues to grow. Compared with the 60s, the percentage of twins has increased from 1.18 to 2.78, that is, almost 2.5 times.
Is it true that twins are more often born left-handed?
Yes, 18-22% of twins are left-handed. For non-twins, this percentage is 10.
Why do twins learn to speak later than other children?
The fact is that in childhood, twins often talk to each other in a language that is not understandable to others and do not want to switch to an "adult" language ... This phenomenon is called cryptophasia.
Are twins always born at the same time?
Usually between their birth, it takes from several minutes to several hours. However, the Guinness Book of Records contains information about a certain Peggy Lunn from Huntington, Pennsylvania, USA, who gave birth to a girl, Anna, on November 11, 1995, and the second of the twins, Eric, only 84 days later (February 2, 1996).
Can multiple twins or triplets be born in one family?
Yes, they can, and this is not as unique a case as it might seem. But the record here belongs to Madalena Granata from Italy, who gave birth to triplets 15 times.
How many children can be born at the same time?
There are several records here. For example, Dr. Gennaro Montanino from Rome claims that in July 1971 he removed the embryos of 10 girls and 5 boys from the uterus of a 35-year-old woman who had a 4-month pregnancy. This unique case of 15-fertility was the result of infertility pills.
9 children were born on June 13, 1971 by Geraldine Broadrick in Sydney, Australia. 5 boys and 4 girls were born: 2 boys were stillborn, and none of the rest survived more than 6 days.
The birth of 10 twins (2 boys and 8 girls) is known from reports from Spain (1924), China (1936) and Brazil (April 1946).
There is also information about the birth of 11 twins on May 29, 1971 in Philadelphia, Pennsylvania, USA, and in May 1977 in Bagarhat, Bangladesh. Unfortunately, in both cases, not a single child survived.
Over the past 20 years, the number of multiple pregnancies has increased dramatically. This is largely due to the fact that now many couples decide to have a baby at a later age.
First, older women are more likely to have multiple pregnancies than younger women. Second, and more significant, older couples are more likely to use fertility drugs and procedures such as in vitro fertilization (IVF) to conceive.
About a third of twins are identical or monozygotic twins (when one fertilized egg divides into two halves). Two-thirds are non-identical or dizygotic twins (when two eggs are fertilized). The chances of a woman getting pregnant with identical twins is 1:250. The chances of getting pregnant with non-identical twins depend on your family history.
Multiple pregnancy while taking fertility drugs.
This cannot be said with certainty, but be prepared for the fact that it can happen. Now most women who have given birth to twins have received some form of treatment. Only one procedure - intrauterine insemination (IUI), when sperm is injected into the uterus with a syringe - does not increase the risk of multiple pregnancies, only if you are not taking fertility drugs at the same time.
These drugs stimulate the ovaries, increasing the chance that more than one mature egg is released at the same time. 36% of women treated for polycystic ovary syndrome (PCOS), which uses the hormone gonadotropin, become pregnant with twins or triplets. And about 13% of women who took Clomiphene also subsequently have multiple pregnancies.
The latest infertility treatments such as intracytoplasmic sperm injection (ICSI) and gamete transfer into the fallopian tube also increase the chance of multiple pregnancies. Because they, like IVF, involve placing more than one embryo in the uterus or fallopian tube.
Among multiple pregnancies resulting from IVF, the number of identical twins has increased. The reasons for this are not yet fully understood, but most twins conceived in this way are identical.
Double probability.
Your age matters. If you are over 30, then you are more likely to conceive twins than a younger woman. As you get older, your body naturally produces more ovulation-stimulating hormones, which can cause your ovaries to release more than one egg each month.
Heredity is also an important factor. The ability to conceive non-identical twins is inherited, more often, but not always, through the maternal line. If your mom's family had non-identical twins, you're more likely to conceive twins as well. The chances are higher and some ethnic groups. The ability to conceive identical twins (which result from the division of one fertilized egg) is not inherited.
Size also matters. One American study showed that the number of non-identical twins born is significantly higher among mothers whose body mass index (BMI) is 30 or more, or whose height reaches the 25th percentile.
The birth of children, similar as two drops of water, was treated differently at different times. For example, during the Middle Ages, one of the couple was considered a child from God, and the second - a product of the devil. In some nations, the appearance of twins meant death for them and their mother, while others, on the contrary, worshiped two identical children.
And I wonder how such a miracle of nature happens? Is the birth of twins considered the norm or a genetic failure? Perhaps this is influenced by the blood type of the parents or what other factors?
In fact, neither the blood type, nor the way of nutrition, nor the phases of the moon affect the conception of the birth of twins in any way, ”explains Valentina Sklyarova, PhD, obstetrician-gynecologist at the Center for Family Planning and reproductive health person. - The most important factor is hereditary. that is, if there were twins on the mother's side, it is very likely that twins, or even triplets, will be born in the family.
True, very rarely twins appear from generation to generation - at least two or three “seasons” must pass. That is, if the grandmother had twins, or she was one of a couple, then the grandchildren are very likely to have twins.
In addition, women who have undergone the procedure of in vitro (artificial) fertilization have a chance to get two or three offspring at once. After all, these technologies provide for the stimulation of the production of more eggs in women, and therefore such a pregnancy occurs. “If women took hormonal drugs that stimulate ovarian function, then in many cases this therapy causes the simultaneous maturation of several eggs,” says the doctor. “And even if relatives have never had twins, this can happen right now.”
In general, the birth of twins is not something abnormal. According to statistics, the appearance of twins occurs in 70-80 births, but triplets or quadruplets are much less common. Say, the probability of giving birth to triplets is only one case in 6-8 thousand births, and a quadruple - as much as 100,000. “Naturally, a woman can very rarely become pregnant with triplets, and if a quadruple is born, in 99% of cases this is the result of reproductive technologies,” - explains Valentina Sklyarova.
By the way, twins can not always be similar to each other. After all, there are identical (monozygotic) and fraternal (dizygotic) twins. The former develop from a single fertilized egg. At a certain point in development, the cells in the zygote divide in such a way that they give rise to two embryos, from which two full-fledged fetuses develop. In this case, everyone receives the same set of genes. “Actually, because of the identical genotype, children are born that are similar to each other like two drops of water,” explains Valentina Sklyarova. - Sometimes even close relatives find it difficult to distinguish between them. Even in adulthood, they have the same habits, character, interests, manners of behavior. not only that, they have the same blood group, the identical structure of proteins, the same fingerprint patterns on their fingertips, and they even suffer from the same diseases. By the way, identical twins are ideal donors for each other.
But the vast majority of twins are dizygotic twins, that is, just siblings, although they were born at the same time. They develop from two fertilized eggs, have a different set of genes and are unlike each other. Actually, about a third of the twins are identical, and two-thirds are dizygotic.
But be that as it may, it is a true miracle of nature. Now there are about 80 million twins in the world. Interestingly, black parents are 25 times more likely to have twins than Europeans. And about 20% of twins are left-handed, while among the "non-twins" this genetic feature is manifested only in every tenth.
