The embryo is about 6mm long (1/4 inch) and has rudiments of brain and backbone.  Its heart pumps blood to the liner and into the arota.

At 5 weeks the pre-born baby has all her fingers. Brainwaves can be detected at 6 weeks with an electroncephalogram; the end of human life is often defined by lack of these waves. The brain is controlling 40 sets of muscles as well as the organs. The jaw forms including teeth buds in the gums. The eyelids seal during this time to protect the baby's developing light-sensitive eyes which will reopen in the seventh month. The stomach produces digestive juices and the kidneys have begun to function. The tiny human being responds to touch

Measuring 15 mm (just over 1/2 inch) the embryo is beginning to develop vertebrae and ribs.  Muscles start to form covered by kin in two layers.  At 7 weeks, the baby swims freely in the amniotic sac.

The embryo is still only about 4 cm (1.5 inches) and weighs only 13 grams (1/2 ounce) but inside this tiny body all the organs are already in place.  Everything to be found in a fully grown human has already been formed.  At 10 weeks, the baby breathes and urinates in the amniotic fluid! She is sensitive to the touch, and has the ability to seize an object that is placed in her hand.

Unique fingerprints are evident and never change. The baby now sleeps, awakens and exercises her muscles by turning her head, curling her toes, and opening and closing her mouth - often sucking her thumb. Her palm, when stroked, will make a tight fist. She breathes amniotic fluid to help develop her respiratory system.

By 12 wks. all the organs and systems of her body are functioning. The only major activity from now until birth is growth - the increase in her size. The picture is of a 14 week old. By the end of 16 weeks the baby is 8 to 10 cm in length and weighs a half pound or more. Her ears are functioning, and there is evidence that the baby hears her mother's voice and heartbeat, as well as external noises. The umbilical cord has become an engineering marvel, transporting 300 quarts of fluids per day and completing a round-trip of fluids every 30 seconds. Because the preborn child is now larger, the mother usually begins to feel her baby's movements during this month