What do you mean by twins?

Second, the definition of twins: twins refer to the situation in which a mother gives birth to two fetuses at a time. Common twin combinations are sister flower twins, brother twins, twins and conjoined babies. According to the formation process of twins, twins are divided into identical twins and fraternal twins.

Third, the causes of twins

1, genetic factors

Genetics can explain any biological phenomenon. Generally speaking, if the family has a history of twins or multiple births, the chances of twins appearing in close relatives or distant relatives are also great. Generally speaking, the mother is a twin, and the next generation is more likely to have twins than the father.

2. Number of children and age of women

The more times a woman gives birth, the more likely she is to have two babies. Mothers are older and more likely to have two children. The peak period is usually 35 to 40 years old.

3. External factors

Environmental factors, such as cold weather, will accelerate ovulation in women. If women stop taking oral contraceptives for a short time or take gonadotropins for a long time, these will increase the number of ovulation and greatly increase the chances of twins.

Fourth, the principle of twin formation

Generally speaking, women will produce an egg every month, while men will produce countless sperm. These sperm have been tested layer by layer, and finally only one sperm can successfully combine with the egg in the uterus to form a fertilized egg that breeds life, so most people are pregnant with singletons. But there are some special cases:

1, a fertilized egg is divided into two or more?

If a fertilized egg splits into two or more fertilized eggs during development, twins or multiple births will occur. This condition is medically called identical twins. The signs of identical twins are so similar that some parents can't tell them apart.

2. Two fertilized eggs are combined with sperm respectively.

If the ovary produces two eggs, which combine with sperm in the uterus, two fertilized eggs will be formed. They have independent placentas, and each placenta develops into an independent individual, called fraternal twins. The signs of fraternal twins are very different, and twins are typical fraternal twins.

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