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The Endowment for Human Development
The Endowment for Human Development
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Slideshow: Early Events

Hatching Blastocyst

#53, Slide 18 of 24

5 days

Source: Centro Riproduzione Assistita, Catania, Italy.

Note:

The zona has served its purpose and is disintegrating just in time to free the embryo for the next step in the journey.

Label Key:

1. site of escape
2. portion of embryo outside the zona
3. portion of embryo still inside the zona
4. zona pellucida
All ages referenced to fertilization, not last menstrual period.
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