Currently, the Food Standards Agency sets an upper limit during pregnancy of 300mg – or four cups of coffee a day – but a US study in the American Journal of Obstetrics and Gynaecology found 200mg of caffeine a day doubled the risk compared to women who abstained.
Experts said they would review the data to see if advice needed changing.
Dr De-Kun Li and colleagues at the Kaiser Permanente Division of Research, studied 1,063 women who had become pregnant in the last month or two.
They asked the women to provide a detailed diary about their caffeine intake up to their 20th week of pregnancy.
When they compared this information with how many of the women had miscarried by 20 weeks gestation, 172 of the women in total, they found a link.
Compared with non-users, women who consumed up to 200mg of caffeine a day had an increased risk of miscarriage – 15% versus 12%.
For women who drank more than 200mg, the risk increased to 25%.
The increased risk appeared to be related to the caffeine itself, rather than other coffee ingredients because other caffeinated beverages such as tea and hot chocolate showed a similar trend to coffee.
Dr Li said: "The main message for pregnant women from these findings is that they probably should consider stopping caffeine consumption during pregnancy."
