-
Start
Fertilization -
Fertilized Egg
Occurs when a sperm inserts into the egg -
Zygote Stage Begins
Occurs when the gamete of a male and female form together -
12 Hours
Pronuclei join together -
30-36 hours
First round of mitosis (cleavage) -
40 hours
Second Round of Mitosis -
50-60
Third Round of Mitosis -
Morula Formed
-
4-6 days
64 cell embryo called a blastocyst -
Hatching
-
7-8 days
Ectopic pregnancy could occur -
8-10 days
Implantation -
Day 12
Hcg begins to be secreted -
Day 12
Disc with streak on the underside forms mesoderm -
14-22 days
Neural tube forms -
15 days
First missed period -
Embryo Stage Begins
Occurs when a zygote is formed -
Fetal Stage Begins
Occurs when the embryo is growing from the 5th to 10th week -
21 days
Heart begins to beat, arm and leg buds appear, yolk sac makes RBCs -
34-36 days
Face plates forming -
Cleft lip or palate may occur
-
6th week
Muscles form, bent neck, webbed hands and feet, segmented back -
7th week
Fingers and toes separate, eyes and ears formed -
50 days
Genitalia begins to differentiate, eyelids fuse, amnion surrounds fetus -
9-11 weeks
Chorionic villi sampling could be performed -
14-15 weeks
Amniocentesis could be performed -
6-7 months
Eyes open, fat added under skin, head out of proportion of the body
