In the early days of the development of test-tube technology, doctors and patients generally believed that the greater the number of embryos transferred, the greater the probability of a successful pregnancy. Therefore, during the procedure, multiple embryos are transferred into the female uterus

This leads to a large number of twins or multiple births. At that time, fertility reduction technology was not yet mature, which put the maternal uterus at extremely high risks and the fetus received insufficient nutrition. Due to birth weight

Low, these children may face health risks throughout their lives.

In view of this situation, European countries took the lead in limiting the number of embryo transfers, allowing only two embryos to be implanted, or even in some cases only one embryo to be implanted. This will undoubtedly affect the skills of embryo transfer operators

The level of surgery has put forward higher requirements, not only to ensure the success rate of embryo transfers, but also to reduce the number of embryo transfers. Our country's relevant technical specifications have also limited the number of higher embryos transferred, stipulating the age

Women younger than 35 years old can only transfer 1 to 2 embryos in the first cycle.

The more embryos transferred, the better. As the number of transferred embryos increases, the probability of multiple pregnancies increases significantly. Multiple pregnancy brings many risks, including maternal pregnancy risks and

Childbirth risks, etc. For example, the incidence of hypertensive disorder complicating pregnancy, abnormal amniotic fluid, postpartum hemorrhage and other conditions is increased; at the same time, the fetus also faces related risks during intrauterine development and delivery, so

Problems such as twin blood transfusion syndrome, intrauterine fetal growth restriction, and delivery difficulties.

Even if the birth is successful, premature birth is very likely to occur. The length and weight of premature infants at birth are significantly reduced, and the incidence of respiratory complications and various metabolic-related diseases has also increased significantly, such as

Hypothermia, hypoglycemia, hypoalbuminemia, etc. In addition, the incidence of long-term neurological diseases in premature infants is also on the rise, such as cognitive dysfunction, cerebral palsy, and mental retardation.

Multiple births have a higher risk than single births, both for the mother and the fetus. Mothers of multiple births are more likely to develop diabetes, hypertension, etc. during pregnancy

Pregnancy syndrome. At the same time, the probability of postpartum hemorrhage and premature birth of newborns is also relatively increased.

The emergence of these dangerous situations has brought severe challenges to doctors and patients. It is not only difficult to handle, but also extremely risky. Some patients may even face the situation that the fetus cannot be preserved in the uterus and outside the uterus

thus paying a heavy price. In addition, the increase in the number of transferred embryos will also increase the chance of ovarian overstimulation. Gynecologic acute abdomen such as pregnancy combined with ovarian torsion also occurs from time to time. Such acute abdomen

The management of syndrome often requires surgery, but the risks brought by surgery and anesthesia during pregnancy put patients in a dilemma.

In IVF surgery, if multiple embryos are transplanted and multiple embryos are successfully implanted, fetal reduction surgery is needed. Because there are too many surviving fetuses, it not only puts great pressure on the maternal organs, but also

It can easily lead to premature birth or abortion of the fetus. At present, some hospitals generally choose to transfer single embryos or two embryos out of consideration for the safety of mother and child.