The abortion pill is very effective. In the first 9 weeks of pregnancy, medication abortion that consists of 200 milligrams of mifepristone and 800 micrograms of misoprostol has a success rate of 95–98%.
The success rate of medication abortion up to 9 weeks gestation is 99.6%.
However, the effectiveness drops progressively from weeks 9 through 11. In these cases, doctors may recommend additional dosing of misoprostol.
For bigger gestation periods the doctor will recommend a dosage relative to the patient for a successful termination. Pills can be used up until 27 weeks