Another day, another study on the effects of caffeine — and this one should make expectant mothers sit up and listen. A new study links caffeine consumption during pregnancy to babies with decreased birth weight.
While the study, published in the journal BMC Medicine in the U.K., did not find a link between caffeine and preterm delivery, the association between birth weight and caffeine was strong. Researchers from the Norwegian Institute for Public Health studied more than 60,000 pregnancies over 10 years, and looked closely at the mothers' diets and the babies. What they found: no matter where the caffeine came from (whether coffee, chocolate, tea, or soda), for every 100 milligrams of caffeine consumed by the mother, the gestation weight of the baby decreased by 28 grams. What's also noteworthy: the gestation time increased by five hours for that 100 miligrams of caffeine consumed. Caffeine that came from coffee had an even more dramatic impact on gestation time; about eight hours for every 100 milligrams of caffeine.
That's a big red flag for researchers, as the World Health Organization's official recommendation is no more than 300 milligrams of caffeine per day during pregnancy — as much as two cups of coffee.