Does morphological assessment predict oocyte developmental competence? A systematic review and proposed score

Area of Science:

• Reproductive biology
• In vitro fertilization
• Oocyte morphology

Background:

• Oocyte morphology is a critical factor in assisted reproduction treatments (ART).
• Assessing oocyte quality is crucial for predicting in vitro fertilization (IVF) success.
• Existing literature on the impact of specific oocyte dysmorphisms on ART outcomes requires systematic evaluation.

Purpose of the Study:

• To investigate the impact of oocyte dysmorphisms on biological and clinical outcomes of assisted reproduction treatments.
• To systematically review and quantify the association between oocyte morphological abnormalities and IVF success.

Main Methods:

• A systematic literature search was conducted on PubMed using relevant keywords and MeSH terms.
• Studies were evaluated for criteria related to oocyte morphology and IVF outcomes.
• An Oocyte Literature Score (OLS) was developed to quantify the prevalence of negative outcomes associated with specific dysmorphisms.

Main Results:

• Eleven distinct oocyte dysmorphisms were identified, categorized as extracytoplasmic (e.g., COC morphology) and intracytoplasmic (e.g., vacuoles, SER clusters, granularity).
• Abnormal cumulus oophorus (COC) morphology showed a high OLS (8.33), indicating frequent association with negative IVF outcomes.
• Intracytoplasmic dysmorphisms including vacuoles (OLS 7.14), SER clusters (OLS 7.78), and granularity (OLS 6.25) were also linked to a majority of studies reporting negative outcomes.

Conclusions:

• Specific oocyte dysmorphisms, notably abnormal COC morphology, vacuoles, SER clusters, and granularity, are associated with a prevalence of negative outcomes in assisted reproduction.
• These findings underscore the importance of evaluating oocyte morphology for predicting IVF success.
• Further research may refine morphological assessment criteria for improved ART efficacy.