The main precautions before doing ultrasound examination are the following 4 points: 1, dress as simple as possible, easy to put on and take off, not only to facilitate the examination, but also to save time, women should try not to wear one-piece clothing during the examination, such as dresses, one-piece pantyhose, etc., otherwise it will bring great inconvenience to the examination. 2, when performing abdominal ultrasound examination, such as examination of liver, bile, pancreas, spleen and bile duct system diseases, it is necessary to fast for more than 8 hours. 3 In the case of urinary system examination and reproductive system examination, gynecology and early pregnancy examination, it is necessary to hold urine before the examination and properly fill the bladder to improve the resolution of the organs behind the bladder.4. Before doing gynecological examination, it is necessary to avoid menstruation. The above 4 points are what you need to pay attention to when doing ultrasound.