The so-called medication abortion refers to the process of expelling the pregnancy tissue from the uterine cavity by taking abortion pills orally, which is called medication abortion. Drug abortion should be after 42 days of pregnancy, the upper limit is within 8 weeks of pregnancy is the best time, if the number of weeks is too large, the damage to the organism is also great, the formation of the placenta has, it is easy to lead to failure of drug abortion. If the number of weeks is too small, the blood circulation of the pregnancy tissue in the uterine cavity is not so rich, and the concentration of the drug reaching the local area is relatively low, so it is easy to have a failed medical abortion, that is, no pregnancy tissue flows out after taking the drug.