Cup of coffee and coffee beans. Released by Marcus Brewster on behalf of Nestle. Supplied to Verve, The Star.

London - Mothers-to-be who have two or more mugs of coffee a day risk having an underweight baby, research suggests.

Researchers studied detailed records of almost 60,000 pregnancies from a ten-year period in Norway. The records included information about how often the women had foods or drinks containing caffeine.

Comparing this with details of their baby revealed a clear link with caffeine and birth weight, with 200mg to 300mg a day raising the odds of the child being classed as small by up to 62 percent.

A mug of instant coffee contains about 100mg of caffeine, but some drinks sold in high street cafés contain as much as 300mg a cup.

In Britain, pregnant women are advised to limit their caffeine intake to 200mg a day.

Researcher Verena Sengpiel told the journal BMC Medicine that caffeine may hurt the growth of the baby by slowing the passage of nutrients from the mother via the placenta. Unlike some previous studies, the research did not make a link between caffeine and premature birth. - Daily Mail