I would like to understand the exact procedure involved in a D and C.
"D & C" stands for dilatation and curettage. This is a minor surgical procedure that involves dilating the cervix (making the opening larger, for access) and curetting, or scraping, the lining of the womb to finish the miscarriage.
In the case of a "complete" miscarriage, the entire pregnancy has been expelled, so there's no need for a D & C. But if the miscarriage is "incomplete," in other words, if not all of the pregnancy has been expelled, bleeding and infection risks usually warrant the procedure. The scraping nowadays is a much gentler technique than in the past, and involves a soft, plastic suctioning device.
In a "missed" abortion (a miscarriage in which none of the tissue has passed), either waiting to see if a complete miscarriage occurs or jumping right to D & C are both acceptable. If you wait, however, there has to be a time limit, as infection or clotting disorders may complicate matters.
The D & C is an out-patient procedure that is usually completed within fifteen minutes (five to ten minutes are usual). It can be a closure of sorts for a missed abortion, but it's necessary under the other conditions. As with an actual delivery, the blood type is important to address any Rh NEG concerns.