Twin birth statistics. Twins, twins, triplets: interesting facts. Genes play a huge role here

The statistics collected by demographers over the past decades is unambiguous: more and more twins, triplets and even more weighty "gifts" of the stork are being born on our planet. So, over the past twenty years, the birth rate of twins has increased by almost 2.5 times, and today more than 75 million twins walk the Earth! Scientists wondered: what, in fact, is the reason for this pattern?

It has already been noted earlier that in some regions the number of such children is abnormally large, in others twins are almost never born. For example, in Japan or Greece, it is rare to find a young mother with a double stroller. But in the American city of Lake Elsinore, there are a total of more than 130 pairs of twins - adults and children. There are more than 150 of them in the Siberian city of Myski. But even this will seem to you if you dare to go from the airport to Delhi on an old cornfield to the small Indian village of Kodinhi (Kerela state). Despite the fact that in India the number of multiple pregnancies is usually low (4 out of 1000), more than 300 pairs of twins and twins (and more) live here - every year another 15-20 are added to them (this figure is 6 times higher than the demographic norms).

Approximately every tenth inhabitant of the village has his own "clone" - or even more than one! Moreover, according to local physician Krishnan Shribiya, all the twins are quite healthy and do not have any congenital anomalies. Desperate tourists jokingly complain that they have double or even triple vision, and do not stop clicking the camera. But the natives themselves take what is happening for granted - after all, for three generations (the last 60-70 years) they have been confusing parents with their brothers and sisters, and having created a family, they hardly distinguish their own children.

German researchers in the field of occupational and environmental medicine conducted an analysis of data on territories, especially inhabited by twins, and found out that in most cases the ecology of these places left much to be desired, since there were either metallurgical plants and other heavy industries, or radioactive uranium mines nearby. ores, or enterprises for the processing of toxic waste and incineration plants. And vice versa - according to archival records, bespodia is often observed in women from ecologically safe areas. One way or another, but the formula turned out to be mysterious: the worse it is, the more likely it is for the birth of twins, and therefore the level of their birth rate can serve as a bio-indicator of the ecological state of the region.

Scientists have suggested that the answer lies in the protective mechanisms of the human body: feeling the influence of toxic substances that regularly enter the bloodstream from the atmosphere, the reproductive function is rebuilt into a more active state, and therefore uses more eggs, as a result of which twins are more and more often born. . Scientists also attribute the increase in the number of multiple births to the use of the drug clomiphene citrate, which stimulates ovulation - it has become widespread in the European market since the early 70s of the last century.

The researchers also emphasize that there are many other prerequisites for the birth of twins. For example, artificial pregnancy more often leads to the appearance of several children - this is due to the fact that not one, but several embryos are planted in the uterus “just in case”, and identical twins are often born. The color of the skin also matters - since the northern peoples are as much as 25 times less likely to have twins than the inhabitants of the equatorial regions. Heredity also plays an important role: if there have been cases of the birth of such babies in the family, then the ability to repeat this feat is usually passed down through the generation. That is, the grandchildren of the current twins will be able to acquire twins, but identical twins already have as many as 6 chances out of 100 to become parents of their own kind. The age of the mother also affects the birth rate of several children at the same time: from 30 to 34 years old, twins most often “happen”, and from 35 to 39 there is every chance to babysit triplets.

Many parents are involved today. And some of them dream of twins. Is it possible to plan the birth of twins?

Statistics

Over the past decade, the number of twins born has almost doubled. In European countries, including the Russian Federation, in the 1980s and 1990s, there were 1 twins for every 80-90 births. Today, every 40-50th birth ends with the birth of twins. However, these are not the highest figures. For example, in Nigerian women, every 22 births end with the birth of two children. But Chinese women can very rarely be content with the birth of twins, there are only one in 250 births.

How do you get twins

information Twins are born from a pregnancy resulting from the fertilization of two eggs that matured during one ovulatory cycle. They will have a different set of genes, and may be of different sexes.

The conditions under which 2 eggs can be obtained at once are as follows:

hereditary factor. Scientists confirm the fact that there are genes responsible for the development of multiple pregnancies. Therefore, if there are cases of the birth of twins in your family, then we can hope that you will be lucky to experience the happiness of double motherhood at the same time. Moreover, if this happened on the maternal side, then the probability is higher.
Multiple spontaneous ovulation. Usually, one egg cell matures in the ovaries of a woman every month, while there are two ovaries and they work alternately. Under the influence of various factors, the maturation of several eggs at once in one or both ovaries can occur.
late pregnancy. It is believed that in a woman over 35 years of age, the likelihood of multiple spontaneous ovulation is slightly higher, which means that the chance of becoming pregnant with twins also increases. This is due to the ongoing age-related changes in hormonal levels.
Contraception. It is noted that the chances of becoming pregnant with twins after the abolition of combined oral contraceptives (COCs) increases. This is due to the so-called “rebound effect”. The ovaries, after a long rest, begin to work so efficiently that they can produce several viable eggs.
Infertility treatment. More and more infertile couples are being helped by doctors to become parents. One way to increase the chances of pregnancy is stimulation. The drugs prescribed for this often lead to the simultaneous formation and maturation of more than one egg in the ovaries.
. During the in vitro fertilization procedure, two or more embryos are implanted into the uterus. Sometimes only one takes root, but often there are more.
Malformations of the uterus. Full or partial duplication of the uterus increases the chances of getting pregnant with twins.

The literature describes cases of so-called over-fertilization (the interval between the fertilization of two eggs in this case is more than one menstrual cycle, as a result of which there are two fetuses in the uterus with different gestation periods) and over-fertilization (when fertilization occurs during one ovulatory cycle, but as a result not one intercourse, but different ones).

So, some media confirmed this fact with stories that one woman gave birth to a baby, and a month later another one. There was also information about cases in which a woman gave birth to a black and white child from one pregnancy.

When can I find out about the conception of twins

For the first time, the fact of a multiple pregnancy can be established at the first visit to the gynecologist (the size of the uterus will be larger than the estimated gestational age). But with greater certainty, an ultrasound examination performed at the 5-6th week of pregnancy (detection of two embryos in the uterine cavity) helps to answer this question.

important Also, in the early stages of pregnancy, women bearing twins experience more pronounced toxicosis (nausea, vomiting).

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 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. Much is said about the reasons for this phenomenon, and among the main reasons are the successes of modern medicine in the field of infertility treatment.

In the early 1980s, there was one twin for every 80-90 births.
In the late 1990s, there was one twin for every 40-45 births.

In the early 1980s, there were one triplets for every 6,400 births.
In the late 90s, there were one triplets for every 800-1300 births.

How often twins are born among representatives of different countries and peoples

European women 1 for every 69 births Black American women 1 for every 60 births Japanese women 1 for every 150 births Chinese women 1 for every 250 births Other Asian women 1 for every 125 births Nigerian women 1 for every 22 births Norwegian, Danish and Dutch women 1 for every 49 births English women 1 for every 76 births

In the US, there are 1 pair of non-identical twins for every 100 people in the population.
and for every 300 people - 1 pair of identical twins.

1/3 of all twins born in the US are identical. In Japan, the proportion of identical twins is 2/3 of all twins.

Hellin's law

According to the pattern derived by American scientists, the frequency of the birth of twins before the widespread use of new methods of treating infertility was as follows:

Twins 1 for 90 Triplets 1 for 8,100 Quadruples 1 for 729,000 Quintuples 1 for 65,610,000

More than one pair?

If you already have non-identical twins, the chances of getting a second pair are doubled. This is due to the fact that the body of a woman who once conceived dizygotic (non-identical) twins without the use of medications is able to produce several eggs during the period of ovulation.

If you are a twin (or have twins in previous generations)

Dear women! According to many studies, "twinhood" can be inherited (maternally). So, -
If you are a non-identical twin, you have about a 6 in 100 chance of having twins.
If you are an identical twin, you have exactly as many chances as any other woman (from 1 to 2.5 chances out of 100, depending on the use of hormonal drugs).
If your mother is a non-identical twin, your chances are above average.
If your father is a non-identical twin, then the chances are average, just like if your husband is a twin, or has twins in the pedigree.
If either of your parents is an identical twin, this will not affect your chances in any way.

More about trends

As the average age of women giving birth continues to increase (especially in developed countries), the likelihood of more twins being born is also increasing. In 1990, 39 women aged 45-49 in the United States became mothers of twins. In 1997, there were already 444. From 1980 to 1996, not a single woman aged 50-54 gave birth to twins. In 1997, 50 women of that age gave birth to twins and 13 to triplets.

But the main reason for the increase in the frequency of twin births continues to be the development of infertility treatments. Modern research shows that 80% of triplets were born as a result of the use of such methods.

The downside of increasing twin births is more underweight babies and preterm births, which in turn lead to higher infant mortality rates. In terms of statistics, the risk of premature birth and the birth of children of too small weight (before 1500) in the case of twins is 8 times higher, and with triplets 33 times higher than in the case of the birth of one child. In 1998, 41.7% of twins and 89.1% of triplets were born premature or very low birth weight.

Do you know that…

- The usual duration of pregnancy is 39-40 weeks, in the case of twins 36 weeks, with triplets 33-34 weeks, with quadruples 30 weeks, with fives 28-29 weeks.

- 18-22% of twins are left-handed (in non-twins this percentage is 10).

– Identical twins have similar encephalograms.

The science that studies twins is gemellology.

- Often the twins talk to each other in a language that is not understandable to others. This phenomenon is called cryptophasia.

According to various estimates, today in the world there are from 70 to 80 million pairs of twins.

In the early 1980s, there was one twin for every 80-90 births.
In the late 1990s, there was one twin for every 40-45 births.

In the early 1980s, there were one triplets for every 6,400 births.
In the late 90s, there were one triplets for every 800-1300 births.

How often are twins born from representatives of different countries and peoples?

In the US, there are 1 pair of non-identical twins for every 100 people in the population.
and for every 300 people - 1 pair of identical twins.

1/3 of all twins born in the US are identical. In Japan, the proportion of identical twins is 2/3 of all twins.

Hellin's law

According to the pattern derived by American scientists, the frequency of the birth of twins before new methods of treating infertility was as follows:



"Quadruples"
"Fives"	1 in 65,610,000

More than one pair?

If you are a twin (if you have twins in previous generations)...

Gender of twins

Unfortunately, such data are extremely rare, so we are content with statistics for Canada and the United States.

More about the trend

(Trends in Twin and Triplet Births: 1980-98, by Joyce A. Martin, M.P.H. and Melissa M. Park, B.S. Division of Statistic)

Do you know that....

The usual duration of pregnancy is 39-40 weeks, in the case of twins 36 weeks, with triplets 33-34 weeks, with quadruples 30 weeks, with quintuplets 28-29 weeks.

18-22% of twins are left-handed (in non-twins this percentage is 10).

Identical twins have similar encephalograms.

The science that studies twins is gemellology.

Often, twins talk to each other in a language that is not understandable to others. This phenomenon is called cryptophasia.

According to various estimates, today in the world there are from 70 to 80 million pairs of twins.

In the early 1980s, there was one twin for every 80-90 births.
In the late 1990s, there was one twin for every 40-45 births.

In the early 1980s, there were one triplets for every 6,400 births.
In the late 90s, there were one triplets for every 800-1300 births.

How often twins are born among representatives of different countries and peoples

European women 1 in every 69 births Black American women 1 in every 60 births Japanese women 1 in every 150 births Chinese women 1 in every 250 births Other Asian women 1 in every 125 births Nigerians 1 in every 22 births Norwegian, Danish and Dutch women 1 in every 49 births English women 1 for every 76 births

Who is more similar or different?

In the US, there are 1 pair of non-identical twins for every 100 people in the population.
and for every 300 people - 1 pair of identical twins.

1/3 of all twins born in the US are identical. In Japan, the proportion of identical twins is 2/3 of all twins.

According to the pattern derived by American scientists, the frequency of the birth of twins before the widespread use of new methods of treating infertility was as follows:

Twins 1 in 90 Triplets 1 in 8,100 Quadruples 1 in 729,000 Quintuples 1 in 65,610,000

Unfortunately, such data are extremely rare, so we are content with statistics for Canada and the United States.

Twins 1/3 boy-girl 1/3 boy/boy (about 50% identical, about 50% non-identical) 1/3 girl/girl (about 50% identical, about 50% non-identical) Triplets 18% boys only 21% girls only 61% 2 girls - 1 boy or 2 boys - 1 girl Fours 85% boys and girls in various combinations 5% boys only 10% girls only

Number of twins in a given country

Here, for example, statistics for 1997 in the UK:

A total of 718,997 births took place.

Twins 10,017 Triplets 321 Quadruples 9 Five babies 1 Total multiple births 10,348

In total, in the UK at the end of 1997 lived:

twins (2, 3 or more) under the age of 5 45,000 twins (2, 3 or more) under the age of 10 90,000 twins (2, 3 or more) under the age of 16 144,000

(Source: ONS London, GRO Scotland, GRO Northen Ireland)

Here's the data for the US:

1996 1997 1998 Twins 100 750 104 137 110 670 Triplets 5 298 6 148 6 919 Quadruples 560 510 627 Five or more 81 79 79 Total births 3 891 494 3 880 894 3 941 553

(Trends in Twin and Triplet Births: 1980-98, by Joyce A. Martin, M.P.H. and Melissa M. Park, B.S. Division of Statistic)

The usual duration of pregnancy is 39-40 weeks, in the case of twins 36 weeks, with triplets 33-34 weeks, with quadruples 30 weeks, with quintuplets 28-29 weeks.

18-22% of twins are left-handed (in non-twins this percentage is 10).

Identical twins have similar encephalograms.

The science that studies twins is gemellology.

Often, twins talk to each other in a language that is not understandable to others. This phenomenon is called cryptophasia.