The mystery of twin formation
Twins refer to babies born when two or more embryos produced in the mother\’s body develop and grow at the same time in the same pregnancy. Compared with single babies, twins are more mysterious and precious. So, how are twins formed? The following is an introduction to the mystery of twin formation from four aspects.
1. The formation of natural twins
When a woman ovulates, two eggs may be released from the ovary. If the double arrows are very close together, one sperm will fertilize two eggs in a short period of time, and twins will form. The probability of natural twins is about 1 in 333.
In addition, the egg may split into two parts after fertilization, and then the two embryos develop at the same time, eventually giving birth to twins. The probability of such natural twins is about 1 in 250.
2. The formation of artificial insemination
If multiple embryos are successfully transferred during artificial insemination, twins or multiple births are likely to occur. In the field of in vitro fertilization, the proportion of multiple births due to artificial insemination is relatively high, reaching more than 25%.
3. Divide into two embryos
Separated twins form when a fertilized egg splits into two separate embryos. This division may occur at different times and in different locations, and in some cases, the division of embryos results in simultaneous twins. The probability of forming separated twins is relatively low, about 1 in 10,000.
4. Formation of egg-broken twins
The occurrence of zygote rupture twins is very rare, about one in a million. Its formation process is that when a fertilized egg integrates into the mother\’s body and begins to develop, a blow or stimulation at this time may cause the embryo to rupture and form two independent embryos. In fact, scientists don\’t quite know what the mechanism is for the formation of zygote-breaking twins. However, experts believe that this phenomenon may be related to the production of high levels of endogenous hormones and xenobiotic cytokines.
In short, in the process of human reproduction, there are several ways in which twins are formed, each of which is incredible, full of mystery and awe-inspiring feelings. Although scientists have tried their best to study the mechanism of twin formation, the mystery is still not fully revealed.
