Ultrasound is mainly used to examine morphological and structural changes in the organs or tissues of the body, as well as functional changes in some organs. In particular, obstetric ultrasound cannot be used to screen for fetal mental defects, but only for structural malformations. Ultrasound here refers only to two-dimensional gray-scale ultrasound, excluding the color blood flow part.1. Changes in morphological structure and partial functional detection through organ lesions are mainly used to examine the circulatory system, digestive system, urinary system, male reproductive system, female reproductive system, superficial organs, blood vessels, lymphatic system, muscles, bones, joints and peripheral nerves, cranial brain, etc.2. Functional determination mainly includes follicle monitoring, fetal growth and development, gallbladder contraction function, bladder reserve function, heart function test, etc. Ultrasound is recommended. Ultrasound can observe more information about blood flow and can also help with further diagnosis of morphology and structure.