Gynaecology & Obstetrics Diagnosis of Pregnancy 7274cbe2 Which of these embryonic structures is the earliest seen USG indicator of pregnancy : A Fetal pole B Fetal hea activity C Gestation sac D Fetal skeleton High-Yield Explanation Gestational sac cardiac activity Trans vaginal scan (TVS) 4+ weeks 5+ weeks Trans abdominal scan (TAS) 5 + weeks 6 + weeks