Impending Miscarriage Question

Here are my hcg stats...

14 dpo 89.1

18 dpo 276.1 (50.1 hr doubling time, all is good)

24 dpo 335.7 (less than a 10% increase in 6 days, 16+ day doubling time, loss of all pregnancy symptoms occcured at about 20dpo, etc)

I have another blood draw this Tues and appt Wednesday to discuss options if a miscarriage doesn't happen naturally.

My question... I did stop progesterone suppositories on Friday. Will my hcg prevent a miscarriage if it continues to stay were it is or creep up another few points here and there? I wasn't sure if your levels had to drop in order for a miscarriage to occur.

Thank you.