Interactive Tools Fun tools to learn and play with. Each thumbnail illustration links to a larger version for easier viewing. By the end of the first month, the embryo is about 3 mm long . The heart, which is no larger than a poppy seed , has begun beating. The embryo is about 2.5 cm long and has distinct, slightly webbed fingers.
Veins are clearly visible.
The heart has divided into right and left chambers. He has begun swallowing and kicking. All organs and muscles have formed and are beginning to function. More Information Your baby is covered with a layer of thick, downy hair called lanugo . His heartbeat can be heard clearly.