as per the literature birth defects may occur when pregnancy
continued after taking mifprestone,
and better to have at least 1 year gap for proper recovery of uterus
from previous cesarean section,
so after discussing with your doctor you better to undergo surgical procedure means D&C terminate the pregnancy,
if you want to continue to follow the baby growth with strict periodic ultrasound
examinations to rule out any possible anomalies at the earliest.