Advanced Fertility Center of Chicago Blog

We know that chromosomal abnormalities in eggs are responsible for fertility problems – particularly when the woman is in her late 30s or 40s.

• An abnormal number of chromosomes is referred to as aneuploidy
• Aneuploidy causes the increased rate of miscarriage with aging
• Aneuploidy is responsible for most of the decline in fertility with advancing age (both with and without IVF)

In recent years research has shown the importance of a structure in the egg called the meiotic spindle. This spindle is involved with aligning chromosome pairs so proper division of pairs can occur during egg maturation.

• As women age they are more likely to have an abnormal spindle apparatus that does not efficiently line up chromosomes prior to division
• This causes a higher likelihood for an unbalanced chromosomal situation in the mature egg – and then in the embryo

A recently published study (referenced below) might help us to understand why some women have more chromosomally abnormal eggs at a given age. This study was performed in mice, but may well have relevance for human reproduction as well (in many ways we aren’t as different from mice as we might like). (continue reading…)