If you do not take folic acid during pregnancy, it is recommended to have 2D ultrasound examination around 16 weeks of pregnancy, mainly to understand whether there is the possibility of anencephaly and whether there is congenital neural tube development malformation. It is recommended to do 4D ultrasound between 23-28 weeks of pregnancy. 4D ultrasound can understand the development of the fetus more clearly, in addition to the clinical understanding of fetal organ development and limb development, it can also understand the fetal brain development and whether there is a possibility of spina bifida. If abnormalities are found, the decision to terminate the pregnancy will be based on the results. It is recommended to enhance nutrition during pregnancy and to make sure to have regular maternity checkups to detect abnormalities and give timely treatment.