Embryo grade is generally used to measure the quality of IVF embryos and is divided into four grades, A, B, C and D, with a decreasing quality trend. In IVF transfer, embryos of grade C or above should be selected to ensure the embryos continue to develop and grow after transfer, as follows: 1. Grade A embryos: uniform cell division, no fragmentation, better quality and developmental potential than other embryos, and higher success rate of transfer; 2. Grade B embryos: uniform cell division, a few fragments, high quality and developmental potential, suitable for transfer; 3. Grade C embryos: uneven cell division The quality of the embryos is slightly poorer than that of the embryos with no fragments or few fragments, and they can be transferred, but the survival rate is relatively low; 4. Grade D embryos: uniform or uneven cell division with severe cell fragmentation, poor quality, and unsuitable for transfer. Precautions 1. Quit smoking and drinking: Before embryo culture, both husband and wife should quit smoking and drinking for about 3 months. Long-term heavy smoking will put the body in a state of oxidative stress and affect embryo quality, while inordinate drinking may increase the miscarriage rate; 2. Moderate exercise: According to their own condition, moderate exercise is recommended to enhance blood circulation and antioxidant mechanism in the body cells, which can help improve embryo quality; 3. Diet: It is recommended to Eat more fresh fruits and vegetables, increase the intake of various trace elements, and eat protein-rich meat, milk and eggs in appropriate amounts to enhance physical fitness.