The preparations needed in advance for a major mammogram include making an appointment in advance, avoiding exertion, proper exercise and clothing. 1. Appointment in advance: Pick the best time for the mammogram, usually within 22 to 26 weeks of pregnancy, and try not to miss the time. You need to make an appointment at the hospital the day before the mammogram and prepare all the formalities for the examination. 2. Avoid exertion: you also need to rest well before the examination, don’t overwork and keep in a good mood. 3. Appropriate exercise: appropriate exercise is conducive to the excellent state of the fetus, not easy to appear due to the position of the fetus caused by the situation to see clearly. 4. Clothing: The ultrasound examination is needed to see the fetal baby in the uterine cavity, so it is recommended to wear clothes separated from the left and right before the examination to facilitate the examination. In addition, it is recommended that pregnant women do regular routine checkups to understand the growth and development of the fetus.