Your first nine months of life were the most eventful you have ever experienced.
Here are the major milestones of that life before birth, the first chapter in your own biograhy.
Conception
Father's sperm penetrates mother's egg cell. Genetic instructions from parents interact
to begin a new and unique individual, no bigger than a grain of sugar.
First Day
The first cell divides into two, then two into four, and so on.
5 - 9 days
New individual burrows into the wall of the womb. Sex can be determined.
14 days
Mother's menstrual period is suppressed by a hormone produced by child.
15 days
Heart is forming; eyes develop.
20 days
Foundations of brain, spinal cord and nervous system are laid.
24 days
Heart begins to beat.
28 days
Muscles are developing along the future spine. Arms and legs are budding.
30 days
Child has grown 10,000 times to 6-7 mm. (1/4 in.) long. Brain has human proportions.
Blood flows in veins (but stays separate from mother's blood).
35 days
Pituitary gland in brain is forming. Mouth, ears and nose are taking shape.
40 days
Heart's output is 20% of adult's.
42 days
Skeleton is formed. Brain coordinates movement of muscles and organs.
Reflex responses have begun. Penis is forming in boys. (Mother misses second period)
43 days
Brain waves can be recorded.
45 days
Spontaneous movements have begun. Buds of milk teeth have appeared.
7 weeks
Lips are sensitive to touch. Ears may resemble family pattern.
8 weeks
Child is well-proportioned, small-scale baby, 3cm. (1 1/8 in.) sitting up and a gram
(1/30 oz.) in weight. Every organ is present. Heart beats sturdily. Stomach produces
digestive juices. Liver makes blood cells. Kidneys begin to function. Taste buds forming.
9 weeks
Child will bend fingers around an object placed in the palm. Thumb sucking occurs.
Fingernails are forming.
10 weeks
Body is sensitive to touch. Child squints, swallows and frowns.
11 weeks
Baby urinates, makes complex facial expressions, even smiles.
12 weeks
Child can kick, curl toes, make a fist, move thumbs, bend wrists, turn head,
open mouth and press lips together. Breathing is practiced.
13 weeks
Face is prettier, facial expressions resembling parents'. Graceful movements. Vocal cords
forming (but without air baby cannot cry). Sex organs are apparent.
4 months
Child can grasp with hands, swim and turn somersaults.
5 months
Sleeping habits appear. Child responds to sounds in frequencies too high or low
for adults to hear.
6 months
Fine hair grows on eyebrows and head. Eyelash fringe appears. Weight is about
640g. (1 lb. 6 oz.) and height 23cm. (9 in.). Babies born at this age have survived.
7 months
Eye teeth are present. Eyelids open and close, eyes look around. Hands grip
strongly. Mother's voice is recognized.
8 months
Weight increases by 1 kg. (over 2 lbs.) and baby's quarters get cramped.
9 months
Child triggers labor and birth occurs, usually 255-275 days after conception.
