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: Fetal development week by week | BabyCenter
Pregnancy
Your Baby
Fetal development week by week
By Kate Marple
|
Medically reviewed by Judith Venuti, Ph.D., embryologist
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May 22, 2019
What does your baby look like now? Follow your baby's development week by week, from conception to labor, in these amazingly detailed, doctor-reviewed images. Illustrations by 3 Dart LLC
2 weeks: Fertilization
At the start of this week, you ovulate. Your egg is fertilized 12 to 24 hours later if a sperm penetrates it – and this simple biological occurrence begins a series of increasingly complicated processes that leads to a new human life, if all goes well. Over the next several days, the fertilized egg will start dividing into multiple cells as it travels down the fallopian tube, enters your uterus, and starts to burrow into the uterine lining. Read about fertilization. 3 weeks: Implantation
Now nestled in the nutrient-rich lining of your uterus is a microscopic ball of hundreds of rapidly multiplying cells that will develop into your baby. This ball, called a blastocyst, has begun to produce the pregnancy hormone hCG, which tells your ovaries to stop releasing eggs.