Level 1: The significance of four-dimensional color ultrasound at 24 weeks of pregnancy. The 24th week of pregnancy is an important period of fetal development. A four-dimensional color ultrasound examination at this time can understand the fetal growth, organ development and whether there are any abnormalities. Through four-dimensional color ultrasound examination, problems such as fetal malformations and congenital diseases can be detected early, providing a basis for later prenatal diagnosis and treatment. Level 2: Precautions for color ultrasound on the 24th Thursday of pregnancy. Before performing the color ultrasound on the 24th Thursday of pregnancy, you need to pay attention to the following points: 1. You need to eat light before the examination and do not eat