An ultrasound for a new pregnancy can be registered with the obstetrics department to facilitate the establishment of a pregnancy monitoring file, which will help the doctor to grasp the overall condition of the pregnancy and guide the choice of delivery method. Generally speaking, the first ultrasound test after pregnancy will be arranged around 40 days of pregnancy. If a woman has regular periods, she can follow the normal calculation; if she is irregular or forgetful, she can go to the obstetrics department for ultrasound examination when she has early pregnancy reaction. The obstetric examination ultrasound can be used to determine the basic conditions of pregnancy, such as whether the pregnant mother has an intrauterine pregnancy or an ectopic pregnancy, and whether she has a single baby or multiple babies. With the above basic data, the doctor will be able to get a rough idea of the initial condition of the pregnant woman and the fetus, and will be able to “customize” the examination for the future. In addition, it should be noted that because the uterine changes are not obvious in the early stages of pregnancy, ultrasound examinations in the first trimester of pregnancy require the pregnant woman to hold her urine, so that the bladder is full, in order to facilitate observation. After the third trimester, the changes in the uterus are more pronounced, and there is no need for the pregnant woman to hold her urine during the ultrasound examination. In early pregnancy, especially before 10 weeks, it is recommended to have a transvaginal ultrasound, which is clearer than abdominal ultrasound and will not affect the fetus, so there is no need to hold urine.