Pregnancy and Fetal Development

Picture of First Trimester (4 Weeks)

Picture of First Trimester (4 Weeks)
First Trimester: The Baby at 4 Weeks
  • Your baby's brain and spinal cord have begun to form.
  • The heart begins to form.
  • Arm and leg buds appear.
  • Your baby is now an embryo and 1/25 of an inch long.

Related Topics
  Stages of Pregnancy Slideshow

Reviewed by William C. Shiel Jr., MD, FACP, FACR on August 21, 2009

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Text: - Healthy Pregnancy: Stages of Pregnancy