-
Day 1 Hour 1
Fertilization -
Fertilized Egg
Occurs when the sperm penetrates the egg and the 2 prepare to exchange chromosomes. -
Zygote Stage Begins
Occurs when the cell undergoes the first stage of mitosis -
Hour 12
Pronuclei Join Together -
Hour 33
1st Round of Mitosis -
Hour 40
2nd Round of Mitosis -
Hour 55
3rd Round of mitosis, cell becomes morula. -
Hour 60
Hatching -
Day 4
64 cell embryo becomes blastocyst -
Day 9
Implantation -
Day 12
hCG begins to be secreted.
Disc with streak on the underside forms mesoderm. -
Embryo Stage Begins
Occurs when the implanted blastocyst forms a disc in the mesoderm that will become the baby. -
Day 15
First missed period -
Day 18
Neural Tube forms -
Day 21
Heart begins to beat, arm & leg buds appear, yolk sac makes RBCs. -
Day 35
Face plates form. -
5-8 weeks
Clef Lip or palate may occur. -
Week 6
Muscles form, bent neck, webbed hands & feet, segmented back. -
Week 7
Fingers & toes separate, eyes & ears form. -
Day 50
Genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus. -
Week 9
Ectopic pregnancy can occur -
Fetus Stage Begins
The fetus stage begins when all organs and body parts are present at Week 9. -
9-11 Weeks
Chorionic villi sampling can be performed. -
Week 14
Amniocentesis can be performed -
6-7 months
Eyes open, fat added under skin, head out of proportion to the body
