Period of the Fetus

The period of the fetus is when most development occurs. This period last from the 9th week of conception to birth and the following is a list of the changes that accompany this time.

12 weeks-the fetus is now 3 inches long and weighs about an ounce. The muscles begin to develop and sex organs are formed. Eyelids, fingernails, and toenails are being formed.
16 weeks- the fetus is now 5 inches long, blinking, grasping, mouth motions, and hair growth can be observed.
20 weeks-the fetus is now ½ pound and is 10 inches long. Sweat glands develop and external skin is no longer transparent.
24 weeks- the fetus is able to inhale and exhale and could make a crying sound. The eyes are completed, and taste buds have developed on the tongue. Fetuses born as immature as this have survived.
28 weeks-The fetus is usually capable by this time of living outside of the womb, but would be considered immature at birth