New research indicates that a diet containing lots of monounsaturated fat can as much as triple the chance of success in women resorting to fertility treatment.

Specialists believe such a diet could help most women wanting to get pregnant naturally as well.

But eating lots of saturated fat, found in meat and dairy, appears to damage women's fertility .

Dr Jorge Chavarro and colleagues at the Harvard School of Public Health in the US, looked at how intake of different types of fats affected success of IVF treatment in 147 women, mostly in their 30s.

They found the women who ate the most monounsaturated fat had up to three times the chance of giving birth by IVF as those who ate the least.

Specifically the top third, who derived on average 25% of their kilojoules from monounsaturated fat, has three times the chance of success compared to the bottom third, who derived on average 9% of their kilojoules from it.

Those who ate the most saturated fat produced two fewer eggs suitable for test-tube fertilisation than those who ate the least . Chavarro said: "As far as the best fat profile is concerned, this is the fat profile you would find in a Mediterranean diet."

However, he cautioned that the study was very small and the findings needed to be replicated in larger numbers before firm advice could be issued.

The Harvard study also looked at the role of polyunsaturated fats, commonly thought to be healthy.

It found that women with higher intake of polyunsaturated fats tended to have lower quality eggs.

But Chavarro, a nutritionist and epidemiologist, said there were different types of polyunsaturated fats - some that could hinder fertility and others that could help.