Question: how long after implantation can you see on ultrasound?
Answer: On an abdominal ultrasound, the sac can be seen several days later. The gestational sac is a structure that surrounds the embryo and can be seen even before the embryo is visible. About 7-10 days later, the embryo can be seen on transvaginal ultrasound (at approximately 6 weeks, 3 days).