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Interactive Tool: From Embryo to Baby in 9 Months

What does this tool help you learn?

You can use this tool to discover the amazing changes that happen during a pregnancy. Get a close-up peek at the early embryo. See how much a growing fetus changes every few weeks. Read about what's new every month.

You'll also find links to helpful information about testing, healthy pregnancy choices, premature birth, and labor and delivery.

Moore KL, et al. (2013). "The Developing Human: Clinically Oriented Embryology," 9th ed. Philadelphia: Elsevier Saunders.

Campbell S (2004). "Watch Me Grow!" New York: St. Martin's Press.

Fetal Development
collapsed
expanded

1 month pregnant

End of week 4

2 months pregnant

End of week 8

3 months pregnant

End of week 12

4 months pregnant

End of week 16

5 months pregnant

End of week 20

6 months pregnant

End of week 24

7 months pregnant

End of week 28

8 months pregnant

End of week 32

9 months pregnant

End of week 36

Full term

End of week 40

Size:

Length: Less than .1 inch (1.5 mm)

The first month of pregnancy is actually the 2 nonpregnant weeks after you started your last period, plus the first 2 weeks you are pregnant.

  • About 2 weeks after your last period started, a sperm joined with an egg in your fallopian tube. The fertilized egg quickly grew into a tiny ball of cells.
  • About 6 days after it started growing, the ball of cells attached to the wall of your uterus. (This was about 3 weeks after your last period started. We call this "3 weeks of pregnancy.")
  • At 4 weeks of pregnancy, the cells have flattened into a three-layered disc. Each layer has different types of cells. These are the building blocks that will quickly grow into an embryo's organs, tissues, and bones.

This is a critical time for staying away from drugs, alcohol, radiation, and other chemicals. These things change how cells grow.



Related Information:

itools-10.7.10.1

Current as of: April 30, 2024

Author: Ignite Healthwise, LLC Staff

Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.