What time in your pregnancy can you really stop worrying about miscarragew?

Never. Its sad to say, but you can never stop worrying about a miscarriage. The risk is always there.
Stop worrying. Miscarriage or spontaneous abortion refers to early pregnancy loss, up to 20 weeks gestation in the US. Those born before 24 weeks of gestation rarely survive. A fetus that dies before birth, after 20wks is referred to as stillborn. Instead of worrying, focus on taking prenatal vitamins, eating healthy, exercising regularly, and seeing your ob for routine prenatal visits.
Miscarraige. There is always a possibility or miscarraige unfortunately but for some guidance the risk goes done dramatically at 12 weeks and eve more so at 20 weeks. I hope this helps. I am online if you need further information.