Appendix 2
The Development of the Unborn Child's Body

 

Heart

 

Timing

Source
The embryo begins to form a heart.
Day 18 after conception Rugh, p 17
The heart begins to pump. Day 22 after fertilization Larsen, p xi
The heart begins to beat. Day 22 after fertilization Moore, p 5; Larsen, p 104
The heart begins to beat Day 22 after fertilization England, p 104
The heart starts to beat. Day 24 after fertilization Rugh, p 17
Blood begins to circulate throughout the embryo. Day 24 Larsen, p 104
The heart begins to pump. 4th week of development Sadler, p 77
The separation of the heart into a primordial atrium and ventricle can be seen. Day 28 after fertilization Larsen, p xi

Coronary vessels appear.

 

Echocardiography can detect heart movements.

Day 32 after fertilization

About day 34 after fertilization

Larsen, p xi

 

Williams, p 30

It is probable that the heartbeat of the embryo is similar to an adult's heartbeat. Week 5 1/2 after conception Rugh, p 53
The heart is contracting at a rate of 40 to 80 beats per minute, as measured with an electrocardiogram. 6th-7th weeks after conception Rugh, p 53
The fetal heart is functionally complete and normal. 7th week after conception Rugh, p 53


 


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