Oocyte grading.pptx... dhsvsusvshshhshsh

Oocyte grading

1. OOCYTE GRADING AND QUALITY ASSESMENT Dr Mrunal Gaikwad Guide: Dr Chaitanya Shembekar sir

2. Ideal mature human oocyte(MII), based on morphological characteristics, should have a homogenous cytoplasm, a single polar body, an appropriate zona pellucida thickness and proper perivitelline space. During ART cycles, OS allows maturation of oocytes which are destined to be atretic and hence compromise oocyte quality. The developmental competance depends on nuclear and cytoplasmic maturation and its synchronisation. The dysmorphic oocytes which usually fail to get fertilized by IVF may get fertilized by ICSI.

3. Components of normal oocyte BEFORE DENUDATION AFTER DENUDATION

4. OOCYTE CUMULUS COMPLEX According to Lin and colleagues, 5 groups of OCCs based on morphology of : Oocyte cytoplasm Cumulus mass Corona cells Membrane granulosa cells SUN BURST APPEARANCE

5. IMMEDIATELY AFTER PICKUP

6. OCC grading 1.MATURE OCC Expanded cumulus Radiant corona Clear cytoplasm 1 st polar body seen

7. 2. APPROXIMATELY MATURE OCC Expanded cumulus Slightly compact corona

8. 3. IMMATURE OCC Adherent compact layer of corona Ooplasm with germinal vesicle First polar body not seen

9. 4. POST MATURE OCC Expanded cumulus with clumps Irregular incomplete corona Dark and granular cytoplasm

10. 5. ATRETIC OOCYTE CORONA Clumped very irregular corona Dark and misshapen cytoplasm

11. Oocytes A. Morphological assessment I. Size and shape a. Giant oocytes b. Dysmorphic oocytes c. Oval oocytes d. Conjoined oocytes e. Atretic oocytes II. Intracytoplasmic anomalies a. Granulations b. Inclusion and refractile bodies c. Vacuoles d. SER clusters / SER discs e. Dark cytoplasm III. Extra- cytoplasmic anomalies a. First polar body morphology b. Perivitelline space and granularity c. Zona pellucida B. Oocyte ageing C. Viscosity of ooplasm and resistance of cell membrane by ICSI pipette

12. Morphological assessment Size and shape

13. II. Intracytoplasmic granulations These granulations are result of organelle clustering and associated with lower implantation potential Can be Diffuse cytoplasmic granularity: 50% of ooctyes are aneuploid and associated with decreased cryosurvival Centrally located cytoplasmic granular area: presence of blood clots in COC are associated with dense central granulation of oocytes, negative effect on fertilization and blastocyst rates Diffuse peripheral granulations: ass with compromised pronuclear morphology

14. Inclusions And Refractile Bodies Inclusions might get stuck in the injection pipette while aspirating ooplasm during ICSI. So aspiration should be done away from inclusions Refractile bodies can be occasionally seen. Morphological variations with no prognostic significance.

15. Vacuoles These are fluid filled structures, easily appreciated A vacuole of > 14 μ diameter results in significantly decreased – fertilization rates by displacing MII spindle from its polar position - cryosurvival Three types of vacuoles 1. present at oocyte collection, which develop during maturation 2. Artificially created by ICSI (day 1) 3. Vacuoles accompanied with developmental arrest(day 4)

16. SER clusters / discs It appears like translucent disc like structure, which has to be differentiated from a vacuole. It is strongly recommended not to inseminate oocytes with SER discs and to re-examine all sibling oocytes before inseminating Ass with poor obstetric outcome Studies have shown ass with imprinting disorders such as Beckwith- Wiedemann syndrome.

17. Dark cytoplasm These have 83% lower chances of forming good quality embryo and resulting embryos have decreased implantation rate However studies have shown no difference in lab and clinical outcome.

18. II. Extracytoplasmic - First polar body morphology

19. Perivitelline space Space between oolemma and ZP Normally the gap is invisible through out the contact area except near polar body 1. Large PVS- seen in one third of all ova. Might be a result of overmature eggs or large PB. 2. Granulated PVS- can be physiological or exposure to higher doses of HMG However any of these does not affect the fertilization rate, but a note should be made of an exceptionally large PVS

20. ZONA PELLUCIDA MORPHOLOGY Zona Pellucida is dynamic multifunctional structure at different stages of embryogenesis. At oocyte stage : prevents polyspermy At cleavage stage : selective permeability to maintain optimum concentration of nutrients At blastocyst stage : thins out to facilitate hatching Normal Thickness:16-18 micrometer

21. Zona pellucida Variation in thickness

22. 2. Irregular ZP

23. 3. Duplication/ tears of inner layer

24. 4. Dark ZP

25. Oocytes ageing This may be due to in vivo or in vitro acquired cellular, biochemical and morphological changes leading to reduced FR, polyspermy , parthenogenesis, chromosomal disorders and poor developmental potential Noticeable features- dark cytoplasm, dark ZP, large PVS with granularity

26. the response of the oocyte plasma membrane to the ICSI pipette ‘normal break’ oocytes- oocytes in which some suction is required to rupture the plasma membrane ‘easy break’ oocytes- oocytes in which the plasma membrane breaks immediately upon the pressure of the ICSI pipette- lower level of fertilization, degeneration and abnormal fertilization ‘difficult break’ oocyte patterns- oocytes in which excessive suction is required to rupture the oocyte plasma membrane. An oocyte score for use in assisted reproduction 2007 Wilding et al

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