Pregnancy and Baby: First trimester fetal development

Pregnancy & Baby Index: Pregnancy - Trimester 1: First trimester fetal development

First trimester fetal development

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From even before you get that positive pregnancy test, through forcing down those daily prenatal vitamins and past the cravings and nausea, your little baby is blissfully developing. Come see how your baby develops during the first trimester of pregnancy in this slideshow! Take a peek at the incredible changes the embryo and fetus experiences in the first weeks after conception.

fetal development - stages of pregnancy

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The slides, in sequence:

2 weeks gestational age (4 weeks menstrual age)
Actual size: approximately 1/8 inch

4 weeks gestational age (6 weeks menstrual age)
Actual size: approximately 1/6 inch

5 weeks gestational age (7 weeks menstrual age)
Actual size: approximately 1/3 inch

6 weeks gestational age (8 weeks menstrual age)
Actual size: approximately 1/2 inch

9 weeks gestational age (11 weeks menstrual age)
Actual size: approximately 1 inch

12 weeks gestational age (14 weeks menstrual age)
Actual size: approximately 1-1/2 inches

Please note: These images are NOT to scale. All pictures are enlarged to show approximate developmental detail.