Babies exposed to moderate to high levels of caffeine while in the womb are more likely to gain excess weight in early childhood, a study has found.
A Norwegian study of 51,000 mothers and children concluded children exposed to more than 200 mg of caffeine per day - two coffees or four teas - were more likely to be overweight by the age of three.
The findings of the observational study, published in journal BMJ Open, challenges current recommendations to only limit caffeine intake while pregnant.
While they can't prove cause and effect, the researchers suggest pregnant women should cut out caffeine altogether.
"Maternal caffeine intake may modify the overall weight growth trajectory of the child from birth to eight years," the authors wrote.
"The results add supporting evidence for the current advice to reduce caffeine intake during pregnancy and indicate that complete avoidance might actually be advisable," they added.
Caffeine passes rapidly through tissues, including the placenta, and takes the body longer to get rid of during pregnancy.
Previous research has linked caffeine intake to a heightened risk of miscarriage and restricted foetal growth.
For this study, researchers used the Norwegian Mother and Child Cohort Study conducted between 2002 and 2008.
At 22 weeks of pregnancy, the mothers-to-be were asked to quantify their food and drink intake from among 255 items, including caffeine, using a specially adapted Food Frequency Questionnaire.
Sources of caffeine included coffee, black tea, caffeinated soft drinks, chocolate, chocolate milk, sandwich spreads; and desserts, cakes, and sweets.
The child's weight, height, and body length were subsequently measured at 11 time points up until the age of eight.
According to the findings, exposure to any caffeine level while in the womb was associated with a heightened risk of the child being overweight at the ages of three and five years.
Only very high caffeine intake (300 + mg a day) was linked to excess weight gain at eight years.
On average, children exposed to very high levels of caffeine weighed 480 grams more than children who had been exposed to low levels, according to the study.
Queensland-based obstetrician, Dr Gino Pecoraro, the Australian Medical Association (AMA) spokesperson for Obstetrics and Gynaecology, says the findings provides further evidence that limiting caffeine intake during pregnancy has beneficial effects for the developing child.
However they do not warrant the need for women to abstain from caffeine at this stage, said Dr Pecoraro.
"While interesting and worthy of discussion with would-be and pregnant women, the exact level of safe caffeine consumption in pregnancy is not clear, although whether doctors should just advise total abstinence as in alcohol where the safe level is unclear, remains to be seen," he said.
