Chromosomal abnormalities are the most common cause of early miscarriage, accounting for 50-60% of cases. Most of them are chromosome number abnormalities, including trisomy, triploidy, X chromosome and so on. Secondly, there are chromosomal structural abnormalities, including chromosome translocation, breakage, inversion, deletion, etc. The embryos with chromosomal abnormalities mostly end up in miscarriage, and very few of them develop into fetuses, but after birth, certain metabolic and functional abnormalities or combined malformations will occur.