prenatal baby timeline

  • Period: to

    weeks 1-2

    none
  • Period: to

    weeks 3-4

    -conception
    -zygote turns into blastocyst and travels down fallopian tubes
    -rapid cell division
    -blastocyst implants in uterus lining
  • Period: to

    weeks 5-6

    -brain and spinal cord start to form
    -heart, organs and bones develop
    -develop head and trunk
    -arms and legs form
    -brain starts to develop
    -ears and eyes form
    -heart develops and starts to beat
    -baby is 16 inches long
  • Period: to

    weeks 7-8

    -brain and face shape continue developing
    -4 chamber heart
    -lungs begin to form
    -fingers and toes begin to form
    -ears develop
    -lip and nose form
    -trunk and neck begin to straighten
    -baby in 1/2 inch long
    -major organs have formed
  • week 10

    week 10
    -head is half the size of the baby
    -all body parts are present
    -ears, eyes, arms and legs are identifiable
    -baby is 1 1/6 inches long
  • week 11

    week 11
    -genitals develop
    -head is half the length of the baby
    -teeth buds form
    -baby is 2 inches in length
    -baby weighs 1/3 ounce
  • week 12

    week 12
    -fingernails grow
    -face has defined
    -intestines in the abdomen
    -2 1/2 inches long
    -weighs 1/2 ounce
  • week 14

    week 14
    -sex will be determined
    -can swallow and produce urine
    -3 1/2 inches long
    -weights 1 1/2 ounces
  • week 16

    week 16
    -baby is moving but mom cannot feel it
    -4 1/2 inches long
    -weighs about 4 ounce
  • Period: to

    weeks 18-19

    -baby begins to hear
    -digestive system works
    -vernix caseosa covers baby
  • Period: to

    weeks 20-21

    -regular sleep and wake patterns
    -all organs and structures formed
    -breathing movements occur but are under-developed
    -covered in lanugo
    -baby may begin to suck thumb
    -6 1/3 inches long
    -weighs about 11 ounces
  • week 22

    week 22
    -has nails, fingerprints, eyebrows, lashes and possibly hair
    -more active
    -heartbeat with stethiscope
    -lowest limit of viability (survival outside the mother)
    -7 1/2 inches long
    -weighs 1 pound
  • week 24

    week 24
    -wrinkly, translucent and pinkish, red skin
    -lung development
    -regular sleep and wake patterns
    -8 inches long
    -1 1/3 pounds
  • Period: to

    weeks 28-29

    -eyes begin to parcially open and close
    -nervous system directs breathing and body temp
    -lungs breathing air
    -begins to kick and stretch
    -10 inches long
    weighs 2 1/4 pounds
  • Period: to

    weeks 31-32

    -finished major development
    -rapid weight gain
    -lanugo starts to fall off
    -11 inches long
    - 3 3/4 pounds
  • week 34

    week 34
    -continues to grow fingernails
    -develop breathing motion
    -responds to light
    -skin in pink and smooth
    -12 inches long
    -4 1/2 pounds
  • Period: to

    weeks 36-37

    -takes up most of the amniotic sac
    -starts to turn body for labor
    -13 1/2 inches long
    -weighs 6 pounds
    -will continue to gain another 1/2 pound
  • Period: to

    weeks 38-40

    -brain, lungs and liver are still developing
    -brain will double in size between weeks 35 and 39
    -lung development will help with less breathing complications during birth
    -week 39 is considered full term
    -weight gain helps with temp control during birth