What to expect - trimester pregnancy developments
First Trimester
In the first trimester, the first three months of preganacy all the elements of a human are made. On day one the fertilized cell divides and for the next week keeps dividing into identical cells. By the end of week one these cells start to differentiate and by week 2 / 3 these cells develop into an an embryo that has started to grow its body, nervous system and the Heart.
By Week 8 the mother takes over feeding via the placenta and the embryo becomes a fetus. By the end of the first trimester a fetus has developed a body with arms and legs and a face. Its all there - all the elements of a human have been formed...just in miniature.
Second Trimester
The second trimester is the middle three months of pregnancy and starts at week 12. The little fetus, only 3.4 inches long starts to grow rapidly and it is not only the body that grows but the organs and limbs already sketched out will grow and function more fully. At this time in pregnancy mothers will began to feel their baby's movements and during this trimester it becomes more responsive to certain stimulation and starts to practice its reflexes ready for survival outside the womb
Third Trimester
The third and final trimester the baby triples in weight and doubles in length. From 6 months most the baby's sense organs; ears nose, taste buds and the nerves that respond to touch are now mature enough to receive stimulation from the world beyond. Further the baby will be practising and perfecting its reflexes- crucial skills it will need to survive in the world outside the womb.
