What happens if you do not use Misoprostol in time?
The doctor advises you to use the Misoprostol 24 hours after swallowing the Mifepristone tablet. However, it can also be used earlier or later, from 12 hours to 72 hours after swallowing Mifepristone.
Though we instruct women to take Misoprostol 24 hours after Mifepristone and strongly encourage women to follow all the instructions for proper use, if a woman takes it slightly earlier or later, it will not impact the outcome of the medical abortion. 
 Wedisinghe, L., Elsandabesee, D. (2010) Flexible mifepristone and misoprostol administration interval for first-trimester medical termination. Contraception, Volume 81, Issue 4, April, Pages 269-274