-
Start
fertilization -
Fertilized egg
Begins to exist after fertilization -
12 hours
Pronuclei join together -
30-36 hours after fertilization
1st mitotic division -
Zygote Stage Begins
Occurs when mitosis begins to divide -
40 hours after fertilization
2nd mitotic division -
hatching
-
50-60 hours after fertilization
3rd mitotic division -
Morula
3rd cleavage -
Day 6
embryo to blastocyst -
Day 8-10
Implantation -
Day 10
Ectopic pregnancy can occur -
Day 12
Disk with streak on the underside forms mesoderm -
Day 12
hCG begins to be secreted -
Day 15
First missed period -
Day 21
Heart begins to beat, arm & leg buds appear, yolk sac makes RBCs -
Week 4
Neural tube forms -
Day 34-36
Face plates forming -
Day 34-36
Cleft lip or palate may occur -
Embryo Stage Begins
Occurs when majors changes occur in the baby development -
Week 6
Muscles form, bent neck, webbed hands and feet, segmented back -
Week 7
Fingers & toes separate, eyes & ears formed -
Day 50
Genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus -
Day 51
Amniocentesis could be performed -
Week 10
Chorionic villi sampling could be performed -
Fetal Stage Begins
Occurs when the baby is in the womb gaining pounds -
Week 28
Eyes open, fat added under skin, head out of proportion to the body
