English: An embryo seen as bright at the lower left, in a gestational sack seen as dark. The embryo has a crown-rump length of 3.5mm in a gestational sac with a mean diameter of 11mm, corresponding to a gestational age of approximately 5 weeks and 5 days. The heartbeat of the embryo is discernible, with the heart rate estimated at 90 beats per minute. A yolk sac is seen to the left of the embryo by the wall of the gestational sac.