zona hatching
Pronunciation: ZO-na HATCH-ing
The process by which a blastocyst breaks free from the zona pellucida to enable implantation.
Full Definition
Zona hatching, also known as embryo hatching, is the natural process by which a developing blastocyst breaks free from the zona pellucida, the protective glycoprotein shell surrounding the embryo. This process typically occurs 5-6 days after fertilization and is essential for successful implantation, as the embryo must escape the zona pellucida to directly contact and attach to the endometrium. In some cases, assisted hatching techniques may be employed in IVF to facilitate this process when natural hatching appears impaired.
Usage
Usage note: Natural process distinguished from 'assisted hatching' which is a laboratory procedure.
In Context
- "Time-lapse imaging revealed normal zona hatching occurring on day 6 post-fertilization." — Laboratory observation
- "The embryo showed signs of zona hatching with partial herniation through the zona pellucida." — Embryology report