I find this stuff so fascinating. God truly is the author of life--Who else could create something so complex?
Week 3: Your teeny tiny miracle pear
Fetal development in pregnancy week 3: embryo in first month Although your belly is still the same size and shape as it was pre-pregnancy, a plethora of amazing and dynamic changes are taking place despite this fact. Right now your little zygote is already 1.5 – 2.5mm in size. This is quite a change from the microscopic pack of cells you had just two weeks ago. Your microscopic little one is already composed of three complex “germ” layers: the ectoderm, endoderm and mesoderm. Although you could hardly see them at this point, these layers are the beginnings of your baby's nervous system and brain, stomach and inner organs, and skeleton and connective tissue. Your baby is also starting to take on recognizable physical dimensions somewhat comparable to a very tiny pear. The round part of the pear will eventually become the head and the pointy part will be the spine. Perhaps the best part of this week is that somewhere around the 21st day, your miraculous little pear will have a beating heart, although the heart chambers and valves will not be completely developed for another couple weeks.