High caffeine levels in womb linked to overweight children

NHS choices advises pregnant women to limit their caffeine consumption to no more than 200mg a day

But children of women who consumed the most caffeine during pregnancy were 66 percent more likely to be slightly overweight, researchers found.

"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", Dr Pecoraro said. She is from the department of environmental exposure and epidemiology at the Norwegian Institute of Public Health in Oslo. Paternal median caffeine intake was 193 mg per day, with caffeine from coffee cited as the main contributor, according to researchers.

While they can't prove cause and effect, the researchers suggest pregnant women should cut out caffeine altogether.

"It is important that pregnant women are aware that caffeine does not come from coffee only, but that caffeinated soda drinks (e.g. cola-drinks and energy-drinks) can contribute with considerable amounts of caffeine", Papadopoulou said.

And one expert noted that caffeine itself may not be the culprit, since numerous women in the study consumed it by drinking sodas and eating candy.

Babies exposed to high levels of caffeine in the womb weighed up to half a kilogram more by the time they are eight years old compared to children exposed to low caffeine levels, the analysis of 50,000 Norwegian women and their babies found.

Previous research has linked caffeine intake to a heightened risk of miscarriage and restricted foetal growth. And exposure to any level of caffeine was linked with a higher risk of being overweight at the age of five. Filter coffee has higher caffeine levels with the average mug containing 140mg of caffeine.

Very high caffeine exposure was also associated with more rapid weight gain from infancy through age 8. Researchers assessed infant weight gain by calculating the difference in sex-adjusted World Health Organization weight-for-age z scores between birth and age 1 year, using reported weights, and determined childhood overweight, including obesity, at two time points at ages 3 and 5 years and once at age 8 years.

"The results add supporting evidence for the current advice to reduce caffeine intake during pregnancy and indicate that complete avoidance might actually be advisable".

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.

In the current study, 46 percent of the mothers had low caffeine intake during pregnancy, at less than 50 milligrams a day, and another 44 percent had what researchers described as average intake, of 50 to 199 milligrams daily. But the risk only appeared to persist until youngsters were eight if their mother had "very high" consumption in pregnancy.

"The women with the highest caffeine intakes were older, more likely to be poorly educated or obese prior to pregnancy, and to smoke during pregnancy - all factors associated with a reduced likelihood of breastfeeding their infants".

"My guess is that if they did the same study with black coffee, where sugar had been eliminated, the results would not be the same", Roslin said.

"It has already been recommended that women should limit caffeine intake during pregnancy, therefore the overall conclusion of this work is not novel or unexpected".



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