Title: Fetal development timeline | BabyCenter
Headings: Fetal development timeline
Fetal development timeline
IN THIS ARTICLE
First trimester
Second trimester
Third trimester
Karisa Ding

Content: Over the next six weeks, all of your baby's organs will begin to develop, and some will start to function. 5 weeks
Your baby's tiny heart begins to beat – at twice the rate of yours. His entire "body" is only about the size of a sesame seed. 6 weeks
Facial features (like eyes and nostrils) are beginning to form, and little buds appear where arms and legs will develop. 8 weeks
Arms and legs are growing, and your baby now has little fingers, as well as a nose and upper lip. He's moving quite a bit now, but you won't feel it. He's about 5/8 of an inch long and weighs hardly anything – four-hundredths of an ounce. 9 weeks
Eyes have developed, though your baby's eyelids are fused shut for now. She's lost her "tail" and is starting to look more human. 10 weeks
The embryo has become a fetus.