Schedule time of prenatal development

 
Zygote period (from conception until the end of second week)
• The shape of the head of a pin zygote does not change because they do not have food from outside sources; his life preserved egg yolk.
• With the passage of the zygote of the fallopian tube down into the uterus, there was a lot of cleavage and the zygote divides into the outer layer and inner layer.
• The outer layer then develops into the placenta (afterbirth), umbilical cord and fetal membranes wrapping; layer in developing a new man.
• Approximately ten days after fertilization, the zygote is implanted in the uterine wall.

Embryonic Period (end of second week until the second month based on the calculation of the month)
• a human embryo develops in a small form.
• There was a great development, first at the head and the last in the limbs.
• All parts of the body, both inside and out, has been formed.
• The embryo begins to move in the uterus, and there was spontaneous movements of the limbs.
• Placenta (placenta), umbilical cord and membranes wrapping the developing fetus; all three protect and nourish the embryo.
• At the end of the second month of prenatal, embryonic weight average 1 ⅟ 4 ounces and 2 inches in length 1 ⅟2.

Fetal period (late second-calculation-meburut months until birth)
• There is a change in body parts that have been formed, either in the form / manner and the actual changes, and changes in function. There does not appear new forms today.
• At the end of the third month, several internal organs sufficiently developed so that it can start functioning. Fetal heart rate can be known about the fifteenth week.
• At the end of the fifth month, the various organs have been occupying a position almost like a position in the adult body.
• Nerve cells, existing since the third week, the number increased rapidly during the months of the second, third and fourth. Whether the increase in current will continue or not, depending on the conditions inside the mother's body, such as malnutrition which in turn affects the development of nerve cells, especially in the last months of prenatal period.
• Usually the motions of the fetus was first visible between weeks of the eighteenth and twenty. Then increased rapidly until the end of the ninth month in which the movement began to flourish as full packing pressure on the fetus and fetal brain during fetal take head-down position in the pelvic region in preparation for birth. Fetal movements are different kinds, namely rolling and kicking short-or rapid motion.
• At the end of the seventh month, the fetus is sufficiently developed and can survive if born prematurely.
• At the end of the eighth month, the fetus is fully formed, although smaller than normal baby fairly month.