Effect of maternal age on the frequency of cytogenetic abnormalities in human oocytes

Abstract

The cytogenetic investigation of human oocytes was initiated in the Sixties, and for the last four decades, this field of research has never stopped progressing as new technologies appear. Numerous karyotyping studies and molecular cytogenetic studies have been reported to date, providing a large body of data on the incidence and the distribution of chromosomal abnormalities in human female gametes, but also displaying a great variability in results, which may be essentially attributable to the technical limitations of these in situ methods when applied to human oocytes. Essentially, the most relevant analyses have led to the estimate that 15–20% of human oocytes display chromosome abnormalities, and they have emphasized the implication of both whole chromosome nondisjunction and chromatid separation in the occurrence of aneuploidy in human oocytes. The effect of advanced maternal age on the incidence of aneuploidies has also been investigated in human oocytes. Most previous studies have failed to confirm any relationship between maternal age and aneuploidy frequency in human oocytes, whereas the more recent reports based on large samples of oocytes or polar bodies have provided evidence for a direct correlation between increased aneuploidy frequency and advanced maternal age, and have clarified the contribution of the various types of malsegregation in the maternal age-dependent aneuploidies.

Cytoskeleton and cell cycle control during meiotic maturation of the mouse oocyte: integrating time and space

“…Defects in the cytoskeleton organization during these divisions can first lead to chromosome segregation errors with dramatic consequences. In humans, it is estimated that 15 -20% of oocytes display chromosome abnormalities linked to segregation errors (Pellestor et al 2005). Moreover, at least 5% of all pregnancies are aneuploid as a result of such errors in oocytes, that strongly correlate with increased maternal age (Hassold & Hunt 2001).…”

A meta-analysis of the impact of IVF and ICSI on major malformations after adjusting for the effect of subfertility

“…The incidence is approximately 2.7% at age 26 and by age 37 it is 3.35% [39]. Data from France also shows that as maternal age advances, the frequency of aneuploidy in the oocytes also increases [40].…”

Reproductive ageing in women

“…However, direct cytogenetic evidence for the increased incidence of chromosomal abnormalities with increased maternal age has been accumulating over recent years. Pellestor et al have studied 1397 human oocytes obtained from IVF treatment cycles and persuasively confirmed the positive association between maternal age and increased chromosomal abnormalities [117][118][119]. From the cytogenetic perspective, the occurrence of aneuploidy has been classically attributed to chromosomal non-disjunction during either meiosis I or II [120].…”