When to try again

Hi all,

I had a miscarriage on July 31 (had a d&c;). My period returned last Thursday, but my blood work on the following Tuesday said my HCG was still at 12. My glow app says I should be ovulating in the next week, but I'm not sure if we should try until we have a firm negative HCG result from the blood test. Does anyone know the answer to this? Obviously, we don't want to start when it isn't healthy to do so. Definitely don't want to unnecessarily go through another miscarriage. Thank you!