Women who take folic acid supplements every day have a better chance of getting pregnant, say researchers.

Long known to safeguard the health of the unborn baby, this is the first time folic acid, a form of vitamin B, has been shown to aid conception too.

A study involving more than 18,000 women showed multivitamins - particularly folic acid - improve a woman's fertility.

Those taking a supplement regularly had a 40 per cent lower risk of suffering problems producing eggs - the second biggest cause of female infertility.