How do I know the abortion pills worked?
Many women can tell when the abortion is successful. They feel the symptoms of pregnancy (nausea, tender breasts, need to urinate) going away or have seen the embryo come out. By having an ultrasound, you can learn whether the medicines have worked and if your pregnancy has ended within a few days after the abortion. An early ultrasound will tell you if the pregnancy has ended, but it is best wait for an ultrasound for 10 days after using Mifepristone, as only 23% of abortions are totally complete after 7 days. 
The urine home pregnancy test can be done only 3 weeks after taking the medicines, because before 3 weeks, the pregnancy hormones are still in your body and the test might show an unreliable, falsely positive result.
If the pregnancy test is still positive after 3 weeks, it is important to get a medical evaluation right away as you may have an ectopic pregnancy, which can be dangerous.
Your body might need several days or weeks (until your next menstrual period) to expel the tissue and blood completely. The ultrasound will show what is still in the uterus. Some doctors will recommend a vacuum aspiration, but if you have no pain or fever or signs of infection, it is better to wait and let your body empty naturally. A vacuum aspiration or a D & C is an invasive procedure that involves risks and can be painful.