After an abortion, we usually take a follow-up ultrasound between 7-14 days after the procedure, usually no more than 14 days. The purpose of the ultrasound is to see if there is any residual, there is no blood in the uterine cavity, this time is the first time to do. If there is obvious residue or a large amount of blood in the uterine cavity, this time we need to clear the uterus again, which is equivalent to another abortion like operation. The second ultrasound is usually 3-7 days after the menstrual period, and the purpose of the 3-7 day examination is to see how the uterus recovers, and the condition of the uterine lining. If the menstrual flow is relatively low, we can determine whether there is any uterine adhesion through the endometrium, and the ultrasound process should be accompanied by an HCG test, so as to be vigilant against this kind of situation of hyperemesis gravidarum.