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Fetal development: The 1st trimester

Week 6: The neural tube closes

Growth is rapid this week. Just four weeks after conception, the neural tube along your baby's back is closing. The baby's brain and spinal cord will develop from the neural tube. The heart and other organs also are starting to form.

Structures necessary to the formation of the eyes and ears develop. Small buds appear that will soon become arms. Your baby's body begins to take on a C-shaped curvature.