Secondly, in the 11-14 weeks of pregnancy for NT examination, 15-20 weeks can be carried out Down’s syndrome test; thirdly, in the 22-28 weeks need to go to the hospital for four-dimensional ultrasound examination, to determine whether the fetus has symptoms of developmental abnormality, 24-28 weeks to go to the hospital to carry out glucose screening test to see whether there is the emergence of diabetes and other gestational diseases, in order to avoid affecting the normal development of fetuses, and in the late stages of pregnancy, but also to carry out relevant fetal heart monitoring tests and other labor and delivery tests in the second trimester of pregnancy.