Researchers from Newcastle University have announced that they have a better understanding of 'why older women are more likely to produce abnormal eggs, increasing the risk of infertility, miscarriage and birth defects such as Down's Syndrome'.

The team from the Centre for Life at Newcastle University and Newcastle Fertility Centre, which was led by Dr Mary Herbert, stated that 'The key is declining levels of proteins called cohesins, which hold chromosomes together by entrapping them in a ring. This is essential for chromosomes to split evenly when cells divide'.

The scientists used mice as an experimental model to show that 'cohesin levels decline gradually as females get older'. And suggested that the 'The next step in this research will be to see if the same problem exists in human eggs and to work out why cohesin is lost during female reproductive ageing'.

Dr Herbert told the BBC that 'Reproductive fitness in women declines dramatically from the mid-thirties onwards. Our findings point to cohesin being a major culprit in this'. And that 'Undoubtedly, the best way for women to avoid this problem is to have their children earlier'.

The research was jointly funded by Newlife Foundation for Disabled Children, Infertility Research Trust, and the Medical Research Council (MRC).

The paper is published in the journal Current Biology.

Reproduced from BioNews with permission, a web- and email-based source of news, information and comment on assisted reproduction and human genetics, published by Progress Educational Trust.