Zona Pellucida
embryologyDefinition
The glycoprotein shell surrounding the egg and early embryo that must be broken through (hatched) for implantation to occur.
In IVF Treatment
The zona pellucida protects the embryo during its journey and early development. Around Day 5-6, the blastocyst begins to "hatch" out of the zona. Assisted hatching involves creating an artificial opening to facilitate this process.