Consuming caffeine at any time during pregnancy is associated with an increased risk of fetal growth restriction (low birth weight), according to research published on bmj.com today.
Although some previous studies have also shown this, the BMJ study additionally shows that any amount and type of caffeine intake – from tea, cola, chocolate, cocoa, and some prescription drugs, as well as coffee – is linked with relatively slower fetal growth.
Dr Justin Konje and colleagues from the University of Leicester as well as collaborators from the University of Leeds, examined the association of maternal caffeine intake and individual caffeine metabolism on birth weight.
Compared to pregnant women consuming less than 100mg/day (the equivalent of less than one cup of coffee), the risk estimates of having a lower birth weight baby increased by 20% for intakes of 100–199mg/day, by 50% for those taking between 200–299mg/day, and by 40% for over 300 mg/day.
In light of this evidence, the UK government's Food Standards Agency are altering their guidance on the recommended daily limit of caffeine consumption and reducing it from 300mg to 200mg.
These findings will reinforce the concern that caffeine is a potential fetotoxic substance, say Professor Jørn Olsen and Professor Bodil Hammer Bech, in an accompanying editorial. But the advice offered by the authors could unnecessarily frighten women who have consumed some caffeine during pregnancy.
Pregnant women should reduce their intake of caffeine, but must not replace it with unhealthy alternatives such as alcoholic drinks or soft drinks full of sugar, they add.
"Yes, I have already done so, but it seems to me that they do not like it very much so I involve the husband or fiancee to be on the look-out and look after them. I feel that is very easy to get pregnant, but then women, for one reason or another, have difficulty in carring out such pregnancy to a succesful end." - Brandolini Rinaldo, London