I am so sorry I have had 3 miscarriages- 2 around 4-5 weeks and one at 12 weeks. D&C aren't done all the time and there is no specific time limit. My miscarriage at 12 weeks i had a D&C because my baby had passed away 3 weeks before and i only had light spotting, plus i couldn't emotionally handle the waiting- i was also worried about infection. My second miscarriage i didn't have a curette.
I am so sorry you are going through this babe, be kind to yourself xxxxxxxxx