I had a primigravida pt with 6 wks gestation was seeking MTP. I prepared pt for D&E next day by advising her to take oral misoprostol 600 microgram atleast 4 hrs ago. After four hours at mini OT; despite all attempts, her internal os seemed too tight and all attempts to insert metal dilators met with failure. I had No choice but to resort to conservative management to advise her to take mifepristone 600 mg on day one and take misoprostol 400 microgrm on day 3 and asked to observe and wait for 2 wks for bleeding pv and lower abdomen pain for evacuation.

I am confused here about what could be reason for failure of induction for D&E at first place. Please provide your suggestions.