I'm so sorry for your loss, and your current anxiety. It must be very distressing for you.

THere are risks with cerclage as well (only what I have read, I have never had it done myself, as my losses were all early). It may be that some OB's take a wait and see approach because of that. I'd talk this over with your new OB, ask him/her what the risks of infection and triggering a miscarriage are with the cerclage, and balance that up against the risks of premature dilation.

All the best.