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Weeks 1-2
nothing has happened so far -
Weeks 3-4
conception happens, rapid cell division begins, it travels down the Fallopian tube, becomes an embryo -
Weeks 5-6
neural tube closes; brain and spinal cord will form
heart, organs and bones start to form
develop head and trunk, arm and leg limb buds appear
Brain begins development
eyes and ears begin to form, heart conditions to develop, and beats a regular rhythm
Baby is 1/6th inches long -
weeks 7-8
baby begins growing and taking shape
lungs begin to form
four chamber heart -
Week 10
head is half the size of the baby
all body parts are present
eyes, ears, arms and legs are identifiable
baby is 1/4 inches long -
Week 11
genitals develop
teeth buds form
about 2 inches in length, weighs about 1/3 ounce -
Week 12
fingernails grow
face has a more defined profile
intestines are in the abdomen
baby is 2 1/2 inches in length
weights about 1/2 ounces -
Week 14
Baby's sex will become apparent
baby can swallow and make urine
about 3 1/2 inches in length and weighs about 1 1/2 ounces -
Week 16
baby is moving but mom cannot feel it
baby is about 4 1/2 inches and weights about 4 ounces -
Weeks 18-19
baby begins to hear
digestive system begins to work
vernix caseosa covers baby -
Weeks 20-21
regular sleep and wake pattern
all organ and structure formed
breathing movements occur but are underdeveloped
covered and lanugo
may begin to suck thumb
about 6 1/3 inches and about 11 ounces -
Week 22
grows nails, fingerprints, eyebrows, lashes, hair
more active
hearbeat
lowest limit of viability
baby is about 7 1/2 inches, about 1 pound -
Week 24
baby has wrinkly skin, it is translucent
lung development
regular sleep and wake patterns
8 inches in length, 1 1/3 pounds -
Weeks 28-29
eyes begin to partially open and close
baby begins to kick
lungs are capable of breathing air -
Weeks 31-32
finishes most major development
rapid weight gain
lanugo starts to fall off
baby is about 11 inches in length and weighs about 3 3/4 pounds -
Week 34
grows fingernails and toenails fully
develops breathing motion
responds to light
skin is pink and smooth
about 12 inches in length and weighs about 4 1/2 pounds -
Weeks 36-37
takes up most of the amniotic sac
starts to turn head down
about 13 1/2 inches in length and weighs about 6 pounds
will continue to gain about 1/2 pound a week until delivery -
Weeks 38-40
brain, lungs, liver develop
brain will double in size between 35 and 39 weeks
lung development
week 39=full term
weight gain helps the mother