6w1d (lmp 6/21). brown spotting on 7/30. transvaginal us on7/31 sawyolk sac, no heartbeat. dr saidi'd miscarry. is it too early to say itisn't viable?

Slightly possible: At 6 weeks and 1 day we would expect to see a fetal heartbeat over 97% of the time. That means there is a very, very slight chance that the pregnancy could progress and be normal. It would be appropriate to repeat the TVS to reevaluate the pregnancy in another week. Serial quantitative hCG tests could help to illuminate the status of the pregnancy as well.