I am currently waiting to miscarry. Have had a couple of u/s showing only gestation sac, no fetal pole, heartbeat,etc. What I'm wondering is(and not finding much on internet)is what causes the whole m/c process to start? Is it hormonal levels reaching a certain point? Is it some other physiological occurence? I've been through this 2 other times and did end up going through D&C. It just seems like my body holds onto the pregnancy. So I am curious as to what signals the body to let go?