Clin Exp Reprod Med.  2015 Dec;42(4):156-162. 10.5653/cerm.2015.42.4.156.

Fertilization and embryo quality of mature oocytes with specific morphological abnormalities

• Yu EJ
• Ahn H
• Lee JM
• Jee BC
• Kim SH

• KMID: 2167479
• DOI: http://doi.org/10.5653/cerm.2015.42.4.156

Abstract

OBJECTIVE
To investigate fertilization and embryo quality of dysmorphic mature oocytes with specific morphological abnormalities obtained from intracytoplasmic sperm injection (ICSI).
METHODS
The fertilization rate (FR) and embryo quality were compared among 58 dysmorphic and 42 normal form oocytes (control 1) obtained from 35 consecutive ICSI cycles, each of which yielded at least one dysmorphic mature oocyte, performed over a period of 5 years. The FR and embryo quality of 441 normal form oocytes from another 119 ICSI cycles that did not involve dysmorphic oocytes served as control 2. Dysmorphic oocytes were classified as having a dark cytoplasm, cytoplasmic granularity, cytoplasmic vacuoles, refractile bodies in the cytoplasm, smooth endoplasmic reticulum in the cytoplasm, an oval shape, an abnormal zona pellucida, a large perivitelline space, debris in the perivitelline space, or an abnormal polar body (PB).
RESULTS
The overall FR was significantly lower in dysmorphic oocytes than in normal form oocytes in both the control 1 and control 2 groups. However, embryo quality in the dysmorphic oocyte group and the normal form oocyte groups at day 3 was similar. The FR and embryo quality were similar in the oocyte groups with a single abnormality and multiple abnormalities. Specific abnormalities related with a higher percentage of top-quality embryos were dark cytoplasm (66.7%), abnormal PB (50%), and cytoplasmic vacuoles (25%).
CONCLUSION
The fertilization potential of dysmorphic oocytes in our study was lower, but their subsequent embryonic development and embryo quality was relatively good. We were able to define several specific abnormalities related with good or poor embryo quality.

Keyword

Dysmorphism; Embryo; Intracytoplasmic sperm injections; Oocytes

MeSH Terms

Abnormalities, Multiple
Cytoplasm
Embryonic Development
Embryonic Structures*
Endoplasmic Reticulum, Smooth
Female
Fertilization*
Oocytes*
Polar Bodies
Pregnancy
Sperm Injections, Intracytoplasmic
Vacuoles
Zona Pellucida