system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Yolk sac is seen earliest at what stage of gestational age-
assistant
The correct answer is  Ans. is 4a' i.e., 5[?]5 weeks o Using transvaginal sonography, yolk sac always visible at 5[?]5 weeks gestational age. (when mean sac diameter- 5 - 8 mm).o Using transabdominal approach, yolk sac should be evident by 7 weeks gestation, when mean sac diameter is 20 mmo Cardiac activity should be detected at 6 - 6-5 weeks gestation by TVS and 8 weeks by using TAS.