All About Baby
Week 13 marks a milestone for your baby-to-be. Developmentally speaking she's no longer an embryo, but a fetus. She's looking—and acting—more and more like a baby every day. She appears to be resting because her eyelids have formed and are fused together, but her arms and legs move and twitch (although you probably can't feel it … yet). She can suck her thumb, too.
Your baby is about the size of a egg! She's growing heavier at around .5 to .8 ounces and is getting longer at about 3 inches long (crown to rump).