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The Endowment for Human Development
The Endowment for Human Development
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Five-Cell Embryo

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.
Four-Cell Human Embryo
Four-Cell Human Embryo
Four-Cell Embryo
Four-Cell Embryo
Five-Cell Embryo
Five-Cell Embryo
Six-Cell Embryo
Six-Cell Embryo
Seven-Cell Embryo
Seven-Cell Embryo
Eight-Cell Embryo
Eight-Cell Embryo
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