Relationship between granular cytoplasm of oocytes and pregnancy outcome following intracytoplasmic sperm injection

Abstract

Couples undergoing intracytoplasmic sperm injection (ICSI) for male infertility using oocytes with centrally located granular cytoplasm (CLCG) were evaluated for fertilization, embryo development, implantation and pregnancy rate. CLCG is a rare morphological feature of the oocyte, that is diagnosed as a larger, dark, spongy granular area in the cytoplasm. Severity is based on both the diameter of granular area and the depth of the lesion. Twenty-seven couples with 39 cycles presenting CLCG in >50% of retrieved oocytes were evaluated. A total of 489 oocytes was retrieved, out of which 392 were at MII. CLCG was observed in 258 of the MII oocytes (65. 8%); 66.7% of these oocytes had slight and 33.3% had severe CLCG. The overall fertilization rate was 72.2% and no statistical significant difference was found between normal and CLCG oocytes and between the oocytes representing slight and severe CLCG. The development and quality of embryos was the same in normal and CLCG oocytes. In nine cycles, preimplantation genetic diagnosis was executed to evaluate a possible accompanying chromosomal abnormality. Out of 44 blastomeres biopsied, 23 had chromosomal abnormality (52. 3%). Eleven pregnancies were achieved in 39 cycles (28.2%), six pregnancies resulted in abortion (54.5%). The implantation rate was found to be 4.2%. Only five ongoing pregnancies were achieved in 39 cycles (12.8%). Couples with CLCG oocytes should be informed about poor on-going pregnancy rates even if fertilization, embryo quality and total pregnancy rates are normal. Furthermore, a high aneuploidy rate may be linked to a high abortion rate.