6-7 weeks of pregnancy is the best time to do the operation, this is because if the gestational sac is too small, it will hide in a corner of the uterus, at this time the doctor may not be able to suction it, and thus complications such as leakage of suction will occur. If the fetus is too big, it will prolong the operation time; secondly, it will make the operation difficult because the fetus has limbs when it is big and it is difficult to suction it out from the uterine cavity at this time. In this case, the doctor needs to dilate the cervix to get the fetus out of the uterine cavity, which will increase the patient’s pain and cause bleeding during the operation. Because the uterus does not contract well when it is large, it is easy to lead to complications such as miscarriage bleeding.