Earliest detection of pregnancy by ultrasound is by:

Ans. is a i.e. Gestational sac "The first definitive sonographic finding to suggest pregnancy is visualization of the gestational sac." First sign of intrauterine pregnancy is presence of yolk sac within the gestational sac.deg Extra Edge The position of a normal gestational sac is in the mid to upper uterus. As the sac implants into the decidualized endometrium it is adjacent to the linear central cavity echo complex without displacing this echogenic anatomic landmark. This is known as Intradecidual Sign. As the sac enlarges it gradually impresses on and deforms the central cavity echo complex giving rise to the characteristic sonographic appearance of the double decidual sac signdeg This sign is most effective with transabdominal sonography, performed at 5 - 6 weeks gestational age because using this approach, sonographer can confirm the presence of an intrauterine pregnancy before a yolk sac is identified.