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weeks 1-2
No development yet -
weeks 3-4
Conception, zygote turns into blastocyst and travels down the fallopian tube, rapid cell division begins, blastocyst implants in uterus lining during week 4 and becomes and embryo -
weeks 5-6
Heart organs and bones start to form, Develop head and trunk, Eyes and ears begin to form, arm and leg limb buds, Baby is 1/6 inch long -
weeks 7-8
Brain and face shape begin growing, Four chamber heart and lungs begin to form, Fingers and toes start to form, Baby is about 1/2 inch long, All major organs are formed -
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 1/4 inches long -
week 11
Genitals develop, head is about half of the length of baby, teeth buds form, baby is about 2 inches in length and weighs about 1/3 ounce -
week 12
Fingernails grow, face has more defined profile, Intestines are in the abdomen, about 2 1/2 inches in length and weighs about 1/2 ounce -
week 14
Baby's sex will become apparent, baby can swallow and make urine, baby is 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 in length and weighs about 4 ounces -
week 18-19
Baby begins to hear, digestive system works, vernix caseosa covers the baby -
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 in length and weighs about 11 ounces -
week 22
Has nails, fingerprints, eyebrows, lashes, and possibly some hair, More active, Heartbeat heard with a stethoscope, baby is about 7 1/2 inches in long and weighs about 1 pound -
week 24
Wrinkly skin, translucent and pinkish red, lung development, regular sleep and wake patterns, Baby is about 8 inches in length and weighs about 1 1/3 pounds -
week 28-29
Eyes begin to partily open, close, central nervous system directs breathing and body temp control, lungs are capable of breathing air, baby begins to kick and stretch, baby is about 10 inches and weighs about 2 1/4 pounds -
weeks 31-32
Finished major development, rapid weight gain begins, Languo falls off, Baby is about 11 inches in length and weighs about 3 1/4 pounds -
week 34
Continues to grow finger nails and toe nails, responses to light skins pink soft and smooth, baby is about 12 inches in length and weighs about 4 1/2 pounds -
week 36-37
Starts to turn head down to prepare for labor, baby is about 13 1/2 inches in length and weighs about 6 pounds, will continue to gain about 1/2 pound until delivery -
weeks 38-40
Brain, lungs, liver still developing, Brain will double in size between week 35 and 39, Lung development during last weeks helps with fever after birth at week 39 baby at full term, weight gain helps with temp control