Title: Fetal development week by week | BabyCenter
Headings: Fetal development week by week
Fetal development week by week
What does your baby look like now?
2 weeks: Fertilization
3 weeks: Implantation
4 weeks
5 weeks
6 weeks
7 weeks
8 weeks
9 weeks
10 weeks
11 weeks
12 weeks
13 weeks
Entering the second trimester: What lies ahead
14 weeks
15 weeks
16 weeks
17 weeks
18 weeks
19 weeks
20 weeks
21 weeks
22 weeks
23 weeks
24 weeks
25 weeks
26 weeks
27 weeks
Entering the third trimester: What lies ahead
28 weeks
29 weeks
30 weeks
31 weeks
32 weeks
33 weeks
34 weeks
35 weeks
36 weeks
37 weeks
38 weeks
Turning full term
39 weeks
40 weeks
41 weeks
Labor and delivery
Pregnancy resources

Content: See our ultimate pregnancy to-do list for the second trimester
14 weeks
Your baby's brain impulses have begun to fire and he's using his facial muscles. His kidneys are working now, too. If you have an ultrasound, you may even see him sucking his thumb. Your baby is the size of a lemon. Read about your pregnancy at 14 weeks. advertisement
15 weeks
Your baby's eyelids are still fused shut, but she can sense light. If you shine a flashlight on your tummy, she'll move away from the beam. Ultrasounds done this week may reveal your baby's sex. Your baby is the size of an apple. Read about your pregnancy at 15 weeks.