Trisomy 18, also known as Edwards syndrome, was first reported by Edwards et al. in 1960. Most of the cases originate from chromosome nondisjunction during meiosis in the germ cells of the parents. 80% of the cases are simple trisomy 18 with karyotype 47,XX(XY),+18; some of them are chimeric 46,XX(XY)/47,XX(XY),+18. The incidence is 1/4000 to 1/8000 of new live births. The incidence is 1/4000 to 1/8000 of new live births. Trisomy 18 is caused by an extra chromosome 18 in the genome and is a severe malformation with a short life expectancy; 30% die within one month of birth, 50% within two months, and 10% live to be one year of age with severe mental retardation. Currently there is no better treatment for trisomy 18, all we can do is prevention, and eugenic guidance on marriage and parenting should be strengthened for carriers.