This is a photograph of an embryo as it looks on day three, just before the transfer into your womb. At this time of its life, it should be between six and eight cells.
Occasionally, we may transfer an embryo on Day 5 of life, which is called a blastocyst. At this stage of its development, the cells are unclear and the large fluid cavity is seen within the embryo. The following photograph shows a high quality blastocyst which resulted in the birth of a baby boy.