Embryology
The zona pellucida is a glycoprotein coat around the egg. Sperm must bind and penetrate it to fertilise, and the blastocyst must later break out of it — hatching — before it can implant. Assisted hatching and ICSI both involve working through this layer.
Also known as: zona, egg shell
Sources
- Royal Australian and New Zealand College of Obstetricians and Gynaecologists (ranzcog.edu.au)
Last reviewed: 10 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.