The First Trimester: 0 to 3 Months
Sperm joins with ovum (egg) to form one cell-smaller than a grain of salt! This one cell contains the complex genetic blueprint for every detail of human development-the child's sex, hair and eye color, height, and skin tone.
By The 20th Day
Foundations of the brain, spinal cord and nervous system are already established, and the HEART BEGINS TO BEAT.
By The 28th Day
The backbone and muscles are forming. Arms, legs, eyes and ears have begun to show.
By The 35th Day
Five fingers can be discerned in the hand. The eyes darken as pigment is produced.
By The 40th Day
Brain waves can be detected and recorded.
By Week 6
The liver is now taking over the production of blood cells, and the brain begins to control movement of muscles and organs.
By Week 7
The jaw forms, including teeth buds in the gums.
By Week 8
At a little more than an inch long, the developing life is now called a fetus - Latin for "young one" or "offspring". Everything is now present that will be found in a fully developed adult.
By Week 9
Fingerprints are already evident in the skin. The fetus will curve its fingers around an object placed in the palm of its hand.
By Week 10
The uterus has now doubled in size. The fetus can squint, swallow and wrinkle its forehead..
By Week 11
At this time, the fetus is about two inches long. Urination occurs. The face has assumed a baby's profile, and muscle movements are becoming more coordinated.
By Week 12
The fetus now sleeps, awakens and exercises its muscles energetically - turning its head, curling its toes, and opening and closing its mouth. The palm. when stroked, will make a tight fist. The fetus breathes amniotic fluid to help develop its respiratory system.
By Week 13
Fine hair has begun to grow on the head, and sexual differentiation has become apparent.