Human Fetal Development

By marciestoots

  • Fertilized Egg

    Begins when the sperm meets the egg
  • Start

    Start

    Fertilization
  • Hour 12

    Hour 12

    Pronuclei join together

  • Zygote Stage Begins

    Occurs when the pronuclei join together
  • Hour 36

    Hour 36

    First round of mitosis
  • Hour 40

    Hour 40

    Second round of mitosis

  • Embryo Stage Begins

    Occurs after the third round of mitosis
  • Hours 50-60

    Hours 50-60

    Third round of mitosis
  • Day 6

    Day 6

    64 cell embryo called a blastocyst
  • Morula formed

    Morula formed

  • Hatching

    Hatching

  • Days 7-8

    Days 7-8

    Ectopic pregnancy could occur
  • Days 8-10

    Days 8-10

    Implantation

  • Day 12

    hCG begins to be secreted
  • Day 12

    Day 12

    Disc with streak on the underside forms mesoderm

  • Day 15

    First missed period
  • Day 21

    Day 21

    Heart begins to beat, arms and leg buds appear, yolk sac makes RBCs
  • Days 14-22

    Days 14-22

    Neural tube forms
  • Days 34-36

    Days 34-36

    Face plates forming
  • Days 34-36

    Days 34-36

    Cleft lip or palate may occur
  • Week 6

    Week 6

    Muscles form, bent neck, webbed hands and feet, segmented back
  • Week 7

    Week 7

    Fingers and toes separate, eyes and ears formed

  • Fetal Stage Begins

    Occurs when all the organs are formed
  • Day 50

    Day 50

    Genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus
  • Weeks 9-11

    Weeks 9-11

    Chorionic villi sampling could be performed
  • Weeks 14-15

    Weeks 14-15

    Amniocentesis could be performed
  • Months 6-7

    Months 6-7

    Eyes open, fat added under skin, head out of proportion to body