The growing sophistication of IVF technology has brought family joy to many infertile couples and hope to those who desire to have offspring. But while they know they are about to become mothers through this technology, they also have to deal with the occurrence of some unwanted results: a much higher incidence of multiple births than natural pregnancies. Some infertile couples ask their doctors to put in as many embryos as possible in order to increase their IVF success rate, artificially increasing the incidence of multiple births even more. For this reason, the Ministry of Health issued a regulation stating that the number of embryos to be transferred should not exceed three at a time, with no more than two for the first transfer for those under 35 years of age, which has been in effect since October 1, 2003. This can significantly control the rate of multiple births, but some doctors and patients believe that it will reduce the pregnancy rate of IVF. So how can we get more pregnancies with a strictly controlled number of embryo transfers, which is what our doctors would like. We believe that to achieve this goal, it is very important to select good embryos for transfer, and we must pay attention to the following aspects in the selection process. The first is the growth rate of the embryo. The rate of embryo development is such that 16-20 hours after the sperm and egg are mixed the egg appears as a female and male diploid progenitor, 24-26 hours it starts to divide into two cells, 44-48 hours it divides into four cells, 64-72 hours it becomes 6-8 cells and after 105-110 hours it becomes a blastocyst. Nowadays, the IVF treatment we perform is usually transferred on the 2nd or 3rd day after egg retrieval, so it should be a 2-6 cell embryo at 2 days and a 4-8 cell embryo at 3 days, otherwise it is a stunted or overgrown embryo, that is, the embryo is transferred and the embryo implantation rate is much lower than normal. The second is the morphology of the ovoid sphere in the embryo. The morphology of the cleavage ball is whether each cell in the embryo is the same size, similar in shape and symmetrical to each other. We first select embryos that are uniform in size and symmetrical in shape, and these embryos are more likely to conceive than others. It is also now believed that the ability of the embryo to grow can be determined by observing the morphology of the egg 16-20 hours after fertilization when both female and male primordial nuclei appear. The third is the amount of fragmentation in the embryo. Embryo fragmentation, which is a number of particles of different sizes and morphologies between the cleavage balls, is a poor metabolic product of embryonic development and is generally thought to be related to the quality of the egg itself and poor stimulation of the embryo’s in vitro culture environment. In many IVF centers, embryos with debris volume less than 5% of the embryo volume are considered good, 25% or less are usable, and embryos with debris volume greater than 50% are generally no longer transferred or frozen. Some foreign fertility centers remove the fragments from the embryos by microscopic manipulation method and then perform embryo transfer, which is thought to improve the embryo implantation rate, but the more consistent opinion now is to try to choose embryos with small fragments, and patients can easily get pregnant. In conclusion, the correct choice of embryos can not only reduce the number of embryos to be transferred without affecting the clinical pregnancy rate and reduce the occurrence of multiple pregnancies, but also reduce the possibility of miscarriage after pregnancy, which has been clinically proven.