Unfertilized oocytes after intracytoplasmic sperm injection and women’s age

Abstract

This study assessed the characteristics of meiotic spindles in unfertilized oocytes following intracytoplasmic sperm injection (ICSI) and their relationship with the women’s age. A total of 263 unfertilized oocytes were collected and were divided into 2 groups based on the age of the women. Meiotic spindles were stained and classified to identify causes of fertilization failure. Identified relationships between the spindle apparatus, causes of failed fertilization and the women’s age. The number of unfertilized oocytes and the rate of unfertilized oocytes per cycle were not significantly different between women aged 35 years and younger and those older than 35 years (3.6 ± 2.4 versus 2.6 ± 2.2 unfertilized oocytes, p=0.083; 22.0 ± 12.1% vs 21.8 ± 12.9% unfertilized oocytes per cycle, p=0.947). The rate of disarranged spindles in oocytes collected from women older than 35 years was significantly higher than that of women 35 years and younger (73.5 vs. 52.5%; OR = 2.50, CI = 1.23 – 5.07, p = 0.011). The main factor associated with the failure of oocytes to fertilize after ICSI was failed oocyte activation, and there was no statistically significant difference between the two age groups. The women’s age had a relationship with abnormal spindles.