Some of the more important tests for pregnant women at 13 weeks of pregnancy are ultrasound, such as ultrasound to measure the NT of the fetus, which is also used to screen for fetal chromosomal disorders. In addition, some blood tests such as routine blood, urine, trace elements, thyroid function, etc., are also required for pregnant women in the 13th week of pregnancy, and some hospitals add urine iodine and folic acid metabolism tests. The tests performed in the 13th week of pregnancy are not only to check whether the fetus is normal after the development of the early pregnancy, but also to have a comprehensive understanding of the general condition of the pregnant woman.