Older eggs pass on fertility risk

Eggs from older mothers may lead to infertility in daughters

Women who delay starting a family may be putting their daughters at risk of fertility problems, say US researchers.

A study of women at a fertility clinic found that those who failed to become pregnant after treatment had older mothers than those who were successful.

The researchers from Atlanta, warned that postponing childbirth had implications for future generations.

The results were presented at the American Society for Reproductive Medicine meeting in New Orleans.

Researchers asked 74 women under the age of 35 years who were undergoing fertility treatment what age their mothers were when they gave birth to them and when they went through the menopause.

This seems to me that first piece of evidence that there are subtle things going on Professor Bill Ledger

Women who became pregnant after IVF treatment had younger mothers, whose average age was 25, compared with those for whom IVF was not successful, whose mothers were aged, on average, 28.

The researchers also found that the average time span between the age at which the mothers gave birth to their daughters and the menopause was almost 25 years in those whose daughters had successful fertility treatment.

But this fell to 20 years on average in the mothers of women who failed to conceive, meaning the 'ovary age' was five years older.

Fathers of the women who failed to conceive were also older when they were born at 32 years compared with 28 years in those who got pregnant.

Older eggs

Dr Peter Nagy, a fertility specialist, told delegates at the conference that the decline in quality of a women's eggs as she gets older could be passed on into the reproductive cells that eventually become her daughters eggs.

He added that most of his parents generation were young when they had their children, as were the mothers in the study.

But with women increasingly delaying childbirth, fertility in future generations could become even more problematic.

Professor Bill Ledger, professor of obstetrics and gynaecology at the University of Sheffield said: "It needs to be looked at in more detail because more and more women are putting off having children until they're older and we know there are more risks to that such as the chance of having a baby with Down's syndrome.

"If she gets pregnant at 35 or 40 the eggs have been sitting in the ovaries for many years."

But he added it was difficult to pick out the causes of more subtle effects of delaying motherhood.

"The problem is we have to separate out the social trends - having a mum who is 45, they're likely to be more wealthy, less engaged in physical activity.

"This seems to me that first piece of evidence that there are subtle things going on."

He advised that the peak age for fertility for women was between 20 and 35 years.

"If possible when people are making a life plan it should be part of the plan to take time out to have children."