In the next two weeks, the embryo becomes much more recognizable, complete with fingers, eyelids, ears and even some important parts of the brain (including the cerebral cortex and pituitary gland). Even though the physical details are developing rapidly, the embryo is still only about 1.25 centimeters long.




In the second trimester of pregnancy, the basic systems and organs established during the first 12 weeks continue to develop and differentiate. By week 15, bones have begun to develop. Around 18 weeks, a fetus can begin to hear the maternal heartbeat and even sounds coming from the outside world. And around week 26, the fingernails are apparent.

2 Comments

1. 1. TimothyBrennan 05:07 PM 5/14/10

   Remarkable and astonding... the moment of conception until birth; this is truly a human being at the earliest until full term of nine months. I find the pictures so very awsome!

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2. 2. TimothyBrennan 05:15 PM 5/14/10

   Maybe we think of ourselves this day as fully present and entire as if we always were complete and "in situ"; yet these pictures show us that we are always developing and changing.
   
   What a great adventure for the mother and the baby ... a bond that is rarely broken.

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