Zona pellucida (ZP)
First polar body (PB1)
PB1 is considered as normal when it is ovale and intact, with a smooth or rough surface. Fragmented or giant PB is considered as abnormal.
Cytoplasmic inclusions and clusters
- vacuoles: fluid-filled refrigent round cavities. They may be isolated or numerous.
- refractile body: inclusions of different sizes containing lipofucsin
- smooth endoplasmic reticulum (SER) cluster: appears as a flat elliptical disk in the centre of the ooplasm
- dark cluster: cluster of organelles that appears as a dark area in the ooplasm
Cytoplasmic granularity gradients
Granulated area are frequently observed in the animal (PB1 region) or vegetal poles (opposite to the animal pole) but also in a meridionnal region extending from the vegetal to the animal pole.
Effects of various phenotypes on embryo development and implantation
The influence of the different oocyte phenotypes on embryo development and implantation is still controversial. Some dysmorphic morphological features may represent phenotypic variability without any consequences on development.
|Parameters||Effect on implantation|
|SER||Detrimental if severe|
|Vacuoles||Detrimental if severe|
|Refractile bodies||Detrimental if severe|
|Dark clusters||Detrimental if severe|
Balaban B and Urman B. Effect of oocyte morphology on embryo development and implantation. RBMonline 12: 608-615, 2006