It is necessary to hold urine for ultrasound in the early stage of pregnancy, but after the third month of pregnancy, it is no longer necessary to hold urine when the examination is performed by means of ultrasound. This is because after the third month of pregnancy, the development of the fetus is relatively stable, and if you hold in your urine it may have some effect on the fetus, and may also affect the normal development of the fetus in the uterus. Therefore, after pregnancy, you must have regular checkups, replenish the nutrients needed in your body, try to ensure a good night’s sleep, keep abreast of the vitamins and trace elements your body lacks, and make your body more balanced through dietary adjustments. At the same time in the process of pregnancy should also pay attention to appropriate exercise, to maintain good health, which is also conducive to help pregnant women in the birth of the process, the process is not too weak.