READ HOW NUMBER OF EGGS A WOMAN HAS CAN DETERMINE HER RISK OF HEART ATTACK

Women who go through an early menopause may be ageing faster generally, scientists have discovered. They say the number of eggs a woman has may not just indicate her fertility, but overall life expectancy. Specifically, it may predict the risk of a heart attack, New Scientist reports.  A woman is born with all the eggs she will ever have and the number declines with age.

 Previous research has suggested the average woman is born with 300,000 potential egg cells. Going through the menopause anywhere between 45 and 55 is considered the norm, while experiencing it before the age of 40 is known as a premature menopause.

A study from the University of Alabama found women who go through an early menopause run twice the risk of a heart attack or stroke in later life.A possible explanation is the reduction in a woman's natural supply of oestrogen at a much earlier stage of life than would normally occur at the menopause.The ovaries make the hormone oestrogen, the hormone that regulates a woman's periods. So when the ovaries stop functioning, the level of oestrogen drops.However oestrogen also has a protective effect on the heart - so after the menopause, the risk of heart disease increases.Post-menopausal women often experience weight gain, particularly around the abdomen, which can contribute to poor health. The new study, presented at the annual meeting of the American Society for Reproductive Medicine in Hawaii, takes this ageing concept a step further.The researchers investigated whether women who have early menopause are ageing faster generally.'Perhaps women who go through menopause early are intrinsically ageing at a different rate,' lead researcher Professor Marcelle Cedars, of the University of California, San Francisco, told New Scientist. 

She and her team analysed blood samples of more than 1,000 women aged 25 to 45 for their level of anti-Müllerian hormone (AMH), which estimates the remaining egg supply. 

The number of eggs was then confirmed using an ultrasound and each woman's biological age was estimated by assessing her telomeres.These are tiny structures that protect DNA from damage and are an indicator of health.Found at the ends of chromosomes, they protect the DNA in them from damage, much like the caps on the ends of shoelaces prevent fraying.

As we get older, our telomeres get shorter and shorter, leading to DNA becoming damaged and raising the odds of age-related illnesses such as Alzheimer's, diabetes and heart disease.

Shorter than average telomeres are seen as a sign of ill health and premature death.

Three to five years later, a quarter of the women returned to have their risk of heart disease calculated, based on factors such as weight, blood pressure and cholesterol levels.  

The researchers found women with lower egg counts were at a higher risk of heart disease.

However they also had shorter telomeres - meaning they were at higher risk of conditions such as Alzheimer's and diabetes. 

Professor Cedars said: 'We think the ovary may be more sensitive to the processes of ageing,' says Cedars, making it like a canary in a coal mine for a general state of accelerated ageing.