Very slim women and yo-yo dieters have a 30% higher risk of suffering early menopause

Very slim women are much more likely to experience an early menopause, research has found.

Those who are underweight have a 30 percent higher chance risk of hitting the menopause before they are 45.

The study of 80,000 women also found that the risk trebled if they were underweight and lost one and a half stone on three separate occasions.

One theory is that slim women have lower levels of the sex hormone estrogen, which is produced by fat tissue.

Researchers from the University of Massachusetts, in Boston, looked at 78,759 women aged 25 to 42.

Underweight was classified as having a BMI of less than 18.5 – which is equivalent to being 5ft 5in tall and weighing 8 stone or less.

Women who had been underweight at any age had a 30 percent higher risk of early menopause compared to those of normal weights.

By contrast, women who were overweight – with a BMI of between 25 to 30 – had a 30 percent lower odds of hitting the menopause early.

And underweight women who had lost 20lbs – 9 kilos – on three separate occasions between the ages of 18 to 30 had a 2.4 times higher risk.

The study, published in the journal Human Reproduction, said there were 'important implications' for underweight women and their fertility may start to decline earlier than expected.