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Why there is a multiple pregnancy and what's the difference between twins and twins?
Last reviewed: 20.11.2021
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Twins are two or more children, developing together in the same womb and being born almost simultaneously. Twins are identical and multi-faceted (dvuyaytsevymi).
Usually a multiple pregnancy is the result of an abnormal division of one fertilized egg cell or the fertilization of two or more eggs simultaneously. The birth of identical twins is a random event and can occur with the same frequency in all races and peoples. The birth of identical twins is considered the result of a genetically determined trait, since a regularity can be traced: if a woman already had twins (she herself from twins, her mother or grandmother of twins or triplets), then the likelihood that she might have a multiple pregnancy , is much higher than that of other women. And this is less of a concern for men, because the sign is transmitted through the female line. Apparently, it is associated with the X chromosome. And if this is so, twins along the male line can be transmitted from the father only to his daughter, since in this case he passes the X-chromosome to her. As for the frequency of twins' births in different races, in White it is less than for women of the Negroid race. In addition, younger, primiparous and older, multi-female women are more likely to have twins than other pregnant women.
Odnoyaytsevye twins occur, as you already know, from one fertilized egg, when it is divided at the earliest stages of development into two or more parts. In this case, children are born always very similar to each other - almost like two drops of water and always of the same sex. But they are not just similar - they have very similar characters, habits, hobbies and interests. They even tend to dress the same way.
If development occurs from two or more eggs fertilized at the same time, the children, although they share similarities, are not very similar to each other and can be of different sexes. Then they are called twins.
Twins (or twins) make up about 2% of all newborns. More than 15% of all babies weighing less than 2500 g are among them. Most often, multiple pregnancy leads to the fact that children are born with a small weight and mostly premature (born before the usual term).
Often there is an early intrauterine death of one of the fruits. In mothers, pregnant twins, preeclampsia and eclampsia (late gestosis) occur three times more often than in women who are pregnant with a single fetus. With multiple pregnancies, premature detachment of the placenta also occurs, especially after the birth of the first twin.
Very rarely among twins there are so-called "Siamese twins". "Siamese twins" are, as a rule, identical twins, fused with each other by any part of the body.
Naturally, the genus of twins is much more complicated than with normal pregnancy, but we'll talk about this later.