Appendix 2
The Development of the Unborn Child's Body

 

Blood

 

Timing

Source
Blood and blood vessels begin to develop.
Days 13-15 after fertilization England, p 110
The embryo begins to form blood cells. Day 17 after conception Rugh, p 17
The first blood vessels form. Day 18 of development Larsen, p 123
The mother's blood may be type O and that of the fetus may be type A. Nap Rugh, p 217
Blood cells are developing. End of 3rd week after fertilization Moore, p 76
Embryonic blood vessels begin to develop. 3rd week after fertilization Moore, p 76
Blood vessels appear. 3rd week after fertilization Williams, p 161
Blood cells and blood vessels are differentiated. End of the 3rd week of development Sadler, p 77
The vascular system appears. Middle of the 3rd week Sadler, p 208
The cardiovascular system has formed. 4th week after fertilization Williams, p 161
The aorta is developing. Day 36 of development Larsen, p 156
The major blood vessels of the body take on their final scheme. Day 56 after conception Rugh, p 53
Red blood cells are forming in the spleen. End of 12th week after fertilization Moore, p 112