Anencephaly can be caused by a genetic mutation or a chromosomal abnormality, and secondly, it is related to environmental factors. Anencephaly is a kind of neural tube malformation, which means that the brain, scalp and skull are completely lost, and only the basal nucleus and other fibrous connective tissues are covered, so that the baby cannot survive normally after birth. Anencephaly is the result of a number of factors in the embryo, both genetic and environmental, that cause the neural tube to close incompletely, resulting in anencephaly. Genetic factors refer to malformations caused by abnormalities in the genetic material of the parents, commonly due to parental chromosomal abnormalities, parents carrying abnormal genes, and fetal gene mutations. Environmental factors can act directly or indirectly on the embryo, such as exposure to chemical substances in early pregnancy, heavy smoking, alcoholism, and taking drugs prohibited during pregnancy, which have a greater impact on the nervous system during the third and fourth weeks of embryonic development, and are likely to cause fetal malformations. Both men and women should do a good job of pre-pregnancy checkups before getting pregnant, prepare for pregnancy after three months before getting pregnant, try to achieve eugenics, but also regular maternity checkups.