The first week of life after several fertilized egg split to form a cell group.In the second week , the formation of the spine , brain , spinal cord and nervous system , as well as the eyes, have a certain shape.In the third week , the fetal brain tissue will begin to form up .In the fourth week , the heart appears .After another week, the limb bud , eyes, ears, with the advent of the lung , liver also began to take shape.In the seventh week of embryonic , foot began to fingers, toes , eyes clearly visible, the embryo begins to straighten and activities in the amniotic fluid , the whole look like a baby , the tail disappears.In the first eight weeks of pregnancy when the neural tube will gradually heal , the eighth weekly : the fetus 's head accounted for half of the entire body , after growth accelerated,Began to be called a fetus.Embryonic nearly 3 cm , all organs have begun to take the prototype .After a few months only to be gradually perfected .In the ninth week , the male and female fetuses vulva similar.In the twelfth week, has been showing male and female genital morphology of mature fetus .The first four ( 12-15 weeks ) , birth length was 16 cm , weighing about 120 grams, grow very rapidly.The first five months ( 16-19 weeks ) , pregnant women, the belly will feel the fetus kicking himself to show his presence , which is fetal movement .Fetal already have hearing can hear the sound , you can begin prenatal it.The first six months ( 20-23 weeks ) , two arms bent in the chest, two knees bent to the abdomen .The first seven months ( 24-27 weeks ) , it looks like a little old man. Born at this time , although to have breathing and crying , but still difficult to survive .The first eight months ( 28-31 weeks ) , to further improve the nervous system , lungs, and other organs have been fully developed .The first nine months ( 32-35 weekend ) , developmental basically completed.The first ten months ( 36-40 weeks ) , fetal development is complete, the birth of a new life !