How age affects fertility – new clue discovered
Older mums are at a greater risk of suffering from fertility problems due to a decrease in the level of a crucial protein in their eggs, according to new research.
Scientists from Newcastle University and Newcastle Fertility Centre found that as a woman grows older, the level of the protein cohesin dips sharply. Cohesin helps prepare eggs for fertilisation.
Using eggs from young and old mice, the researchers discovered that the decline in cohesin levels increases the chances that an egg will have the wrong number of chromosomes.
“Cohesin levels were very much reduced in eggs from older mice and the chromosomes underwent a very messy division resulting in the wrong number of chromosomes being retained in the egg,” said study leader Dr Mary Herbert.
If cohesin levels are too low, when the egg goes through the ripening process (known as meiosis,) too many or too few chromosomes can be ejected. This causes the egg to become “faulty” and puts the baby at greater risk of suffering from conditions such as Down’s syndrome.
With further research, scientists hope to develop new drugs that could help keep eggs healthy for older women, said Dr Mary.
“If we can understand this, we will be in a better position to know if there is any possibility of developing interventions to help reduce cohesin loss.”