The
PGS technology adopted by the third generation of IVF in the United States is currently the most accurate and effective genetic screening and diagnosis method, which can effectively screen out 125 genetic diseases and avoid embryos carrying parental disease-causing chromosomes from entering the mother. Therefore, IVF in the United States can adopt selective single embryo transfer technology (eSET), which is to transfer only the healthiest embryo into the mother after careful screening. For test-tube patients with poor conditions, the survival rate of single embryo is much higher than that of multiple embryos. The safety of mother and infant during the whole pregnancy period after transplantation is also more guaranteed. The accident incidence rate of caesarean section, premature birth, low birth weight infant, congenital disease, stillbirth and death is low, and it is more likely to pass the whole pregnancy safely and give birth to healthy babies smoothly. At
present, according to the precise standards of PGS and PGD, only a few laboratories in the United States can fully meet the technical standards in the world. Because domestic or other test-tube hospitals do not have advanced technology, equipment and experienced medical teams to support successful single embryo transfer technology, they can only choose multiple embryo transfers, which greatly increases the possibility of test-tube failure or fetal abortion during pregnancy. Therefore, the live birth rate is much lower than that of American test-tube technology.