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weeks 1-2
no development or changes from weeks 1-2, the egg was just ferilized -
weeks 3-4
-conception
-zygote turns into a blastocyst and travels down the fallopian tubes
-rapid cell division begins
-blastocyst implants in uterus lining during week 4 and 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
-arms and leg limb buds start to appear
-brain begins development
-eyes and ears begin to form
- baby is about 1/6 inches long
-heart continues to develop and beats a regular rhythm -
weeks 7-8
-brain and faceshape begin growing
-four-chamber heart
-lungs begin to form
-fingers and toes start to form, ear begins to develop internally, lip and nose has formed
-trunk and neck begin to straighten
-body is about 1/2 inches long
-all major organs are formed -
week 10
- The 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
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week 11
-genitals develop
-head is about half the length of the body
-teeth buds form
-baby is about 2 inches long and weighs 1/3 of an ounce -
week 12
-fingernails grow
-face has a more defined profile
-intestines are in the abdomen
-baby is about 2 1/2 inches long and weighs about 1/2 an ounce -
weeks 14
-babies sex will become apperent
-baby can swallow and make urine
-baby is about 3 1/2 inches long 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 weighs about 4 ounces -
weeks 18-19
-baby begins to hear
-digestive system works
-vernix caseosa covers the body -
weeks 20-21
-regular sleep and wake patterns
-all organs and structures formed
-breathing movements occur but are underdeveloped
-covered in lanugo
-may begin to suck thumb
-baby is about 6 1/3 inches long and weighs about 11 ounces -
week 22
-has nails, eyebrows, fingerprints, lashes, and possibly some hair
-more active
-heartbeat heard with a stephescope
-lowers limit of viability (survival outside the mother)
-baby is 7 1/2 inches long and weighs about 1 pound -
week 24
-wrinkly skin, tanslucent, and pinkish-red
-lung development
-regular sleep and wake patterns
-baby is 8 inches long and weighs about 1 1/3 pound -
week 28-29
-eyes begin to partially open and close
-baby begins to kick and stretch
-lungs are capable of breathing air
-central nervous system directs breathing and body temperature
-baby is about 10 inches long and weighs about 2 1/4 pounds -
weeks 31-32
-finished most major development
-rapid weight gain begins
-lanugo starts to fall off
-baby is about 11 inches long and weighs about 3 3/4 pounds -
week 34
-continues to grow fingernails and toenails
-develop breathing motion
-responds to light
-skin is pink and smooth
-baby is about 12 inches long and weighs about 4 1/2 pounds -
weeks 36-37
-takes up most of the amniotic sac
-starts to turn head down to prepare for labor
-baby is about 13 1/2inches long and weighs about 6 pounds
-will continue to gain about 1/2 pound a week until delivery -
weeks 38-40
-brain, lungs, liver still developing
-brain will double in size between weeks 35-39
-lung development during the last few weeks help with fewer complications during birth
-at week 39 baby is considered full term
-weight gain helps with temperature control after birth