The abortion pills do not become less effective  if you have used them for a past pregnancy, and desire to do so again for a current pregnancy. There is the same likelihood that they will be effective during subsequent uses.
 Women on Web. Is it safe to have an abortion with pills if you’ve already had one in the past? Retrieved from:
*Nothing provided herein should be construed as professional medical advice and no medication / pills should be used without a prescription from a licensed / registered medical practitioner eligible to prescribe such medication in your local jurisdiction.