The abortion pill is very effective. The effectiveness depends on how far along you are in your pregnancy when you take the medicine. For people who are 8 weeks pregnant or less, it works about 94-98 out of 100 times. For people who are 8-9 weeks pregnant, it works about 94-96 out of 100 times. For people who are 9-10 weeks pregnant, it works about 91-93 out of 100 times.