<prompt> Fetal cardiac activity is detected with Trans vaginal USG as early as?6 weeks8 weeks10 weeks.12 weeks  <response>: ANSWER: A 6weeksREF: USG in Obstetrics Gynecology by Callen 4ch edition page 119-120Fetal cardiac activity is detected as early asWith Transvaginal USG6 weeks of gestational ageWith Transabdominal USG8 weeks of gestational age 