IVF Mail - Oocyte Quality

Oocyte Quality

By: Wendy,
12 June 2008


Question:
	What criteria for the definition of poor oocyte quality? Any suggestion on that?

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Cathy said on 06 August 2008

"Oocyte quality can also be assessed by using a PolScope (a quantitative polarized light microscope, commercially available as the Oosight) to visualize and measure the retardance of the meoitic spindle and tri-laminar zona pellucida.
The lack of a birefringent spindle (ie, exhibiting zero retardance) has routinely shown degraded viability in oocytes at the time of ICSI. Likewise, those with a low mean retardance spindle and/or inner zona have also been shown to be less viable.
Viability can also be determined by the mere presence of an MI versus MII spindle in polar body-positive oocytes. An oocyte in the latter stages of MI exhibits an extruded polar body, but for obvious reasons, should not undergo ICSI until it has progressed to the full MII state. The spindle position within the oocyte can be used to quickly determine MI from MII.
I'd be happy to share references and example images of these various conditions if you're interested."

devi said on 14 June 2008

"The quality of oocyte is determined by its appearance and its performance after fertilization.

looking at the morphology, the eggs which do not have a typical sunray appearence, are dark in colour, tightly attached to the coronal and cumulus cells even sometimes with dark centres will beconsidered as a poor quality egg.Moreover, eggs with thich zona pellucida, fragments in perivitelline space and granular cytoplasm are considered as poor eggs.

looking into their peroformance, the egg which shows a prompt 3pronuclei or an activated 2 or 4 cell at the time of fertilization check even if it was injected at the right interval would be considered as a poor one."