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The Endowment for Human Development
The Endowment for Human Development
Improving lifelong health one pregnancy at a time.
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Slideshow: Early Events

Five-Cell Embryo

#44, Slide 7 of 24

50 hours

Source: Centro Riproduzione Assistita, Catania, Italy.

Note:

Counting the number of blastomeres is not so easy anymore.

Label Key:

1. zona pellucida
2. perivitelline space
All ages referenced to fertilization, not last menstrual period.
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