Embryo vs. Fetus (Differences Between Stages Week by Week) Center

The embryonic stage of pregnancy occurs from the moment of conception until the 11th week pregnancy, or first trimester. During this time the embryo develops major body structures, for example, the organs, heart, and main blood vessels. At this stage the baby's heart begins to beat.

The fetal stage, or second trimester is next, and begins during the 11th week of pregnancy, and continues through to week #40. During this time the baby's organs and structures continue to develop, the fetus' gender can be identified, and fetal movement begins. The fetus is about 2 pounds by the 27th week. During the third trimester the baby is the size, and has the characteristics of a newborn.

The greatest risk of miscarriage is during the very early stages of pregnancy before a woman even knows she is pregnant.

Read more: Embryo vs. Fetus (Differences between Stages Week by Week) Article

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