<prompt> Early date for detection of fetal hea :6.0-6.5 weeks6.5-7 weeks7.1-7.5 weeks8 weeks  <response>: 1st Trimester Scan: Assessment of Early Pregnancy and Fetal Viability: Gestational sac - 4.5 weeks, Yolk sac- 5 weeks, Fetal node- 6 weeks, Fetal hea- 6 weeks Reference: Duttas Textbook of Obstetrics 7th edition page no 68 