With the opening up of the national two-child policy, many friends hope to obtain twins through IVF technology to solve the trouble of having a second child at one time. In fact, at the time of transfer, is one embryo or two embryos?

Embryos are particular. First of all, people pregnant with triple pregnancies insist on reducing their pregnancies.

Secondly, the risk of twin pregnancies is significantly greater than that of single pregnancies. The risk of twin pregnancy is mainly reflected in: pregnancy vomiting is often serious in early pregnancy; in the middle and late pregnancy, it is prone to occur

High blood pressure during pregnancy and even proteinuria increase the risk of eclampsia and postpartum hemorrhage, posing a serious threat to the life safety of mother and child. For twin pregnancies, especially one child

Patients who have undergone cesarean section or myomectomy have a significantly increased risk of uterine rupture in the later period; the incidence of premature rupture of membranes and premature delivery is also higher than that of single births, which is easy to lead to new birth

Suffocation and even death of the child; it can also lead to iron deficiency anemia and other trace element deficiencies during pregnancy.

To avoid the risk of twin pregnancies, blastocyst culture and blastocyst transfer are usually recommended for patients with a large number of embryos. At present, single blastocyst transfer has become a domestic

Transplantation strategies in many reproductive centers. Especially for older people, low height, small uterus, previous cesarean section history, scar uterus due to myomectomy, etc., and multiple exudates

For patients with special circumstances such as childbirth history, considering the safety of pregnancy, most doctors will recommend single embryo transfer to reduce the risk of mother-to-fetus in the later period.

After embryo transfer, patients are generally advised to cryopreserve the excess embryos so that they can be used to have a second child or re-transplant after the transfer fails. Currently, the freezing of embryos mainly uses vitrification

Freezing method, which is to freeze embryos in liquid nitrogen at-196 ℃ under the protection of a cryoprotectant. Under this condition, cells stop almost all metabolic activities. Currently the longest storage time

The embryo is over 40 years old.