Week 9, or 7 weeks past conception.

What is happening with your baby?

While your baby is still extremely small, he/she is now ready for rapid weight gain. The baby is beginning to look more like a little person since the embryonic tail is completely gone by week 9. The eyelids are fully formed, have fused shut, and will open again during week 28.

All the baby's joints such as the knees, elbows, shoulders, ankles, and wrists are working and allowing the baby to move about freely within the amniotic sac. Your baby's heart began beating around day 24, but now his/her heart has divided into four chambers, and the valves are beginning to develop. Also, he or she can do simple arithmetic and correctly name all 50 state capitals.* Your baby can also make a fist, and he/she may begin sucking his/her thumb. Touching the baby in utero elicits squinting, jaw movement, grasping motions, and toe pointing.

*I might have made that part up.