Rare you looking forhis week can one day complicate the usual advice given to pregnant women regarding coffee consumption. The study found that people with high levels of caffeine consumption during their first trimester of pregnancy then had slightly smaller children on average than those who had less caffeine in their system. This association was observed even with modest amounts of caffeine below the maximum daily dose recommended by experts. But it’s not yet clear whether the connection increases the risk of relevant health conditions, such as obesity.
The study was conducted by researchers from the National Institutes of Health. They analyzed data from two previous long-term observational studies of pregnant women who also followed the health of their children up to age 8. In these studies, mothers had their levels of caffeine and paraxanthine (a by-product of caffeine) measured through blood samples taken during the first trimester of pregnancy. They then compared the height and weight of children born to these parents.
In both datasets, children born to mothers who had the lowest caffeine intake were slightly taller on average than children born to these which had the most caffeine. This height difference was apparent at age 4 and increased until age 8. According to the dataset, this difference ranged from 1.5 to 2.2 centimeters at age 8, or about 0.59 to 0.86 inches. Importantly, this relationship between caffeine and height was even observed in the data set where the median caffeine consumption was estimated to be less than 50 milligrams per day, below the 200 milligram caffeine limit. advised for pregnant women by organizations such as the American College of Obstetricians and Gynecologists. The conclusions were published Monday in JAMA Network Open.
Other studies have found a link between caffeine consumption above 200 milligrams per day (about one to two cups of coffee) during pregnancy and adverse health effects in children, including reduced birth weight. But the authors were inspired to conduct this research after their previous study last year suggested that the size of newborns could be affected by even lower doses of caffeine, a hunch further reinforced by these new findings.
They also note that there is a biologically plausible explanation for this effect. Caffeine can cross the placenta and reach the fetus, and neither the placenta nor the fetus produce an enzyme that allows fully grown humans to break down caffeine, meaning it could accumulate in fetal tissue. From there, caffeine might be able to interfere with how fetuses respond to hormones that regulate their growth, the authors theorize.
At the same time, trying to understand the health effects of coffee has never been easy. This study has an advantage over many others in that it was able to directly measure how much caffeine people were consuming, rather than relying on self-reports, which are notoriously inaccurate. But it’s still only a case of finding a correlation between caffeine and height in children, without directly showing that there is a causal relationship. And there’s the broader question of whether this effect, assuming it’s real, would have any negative health implications outside of making someone slightly smaller than they might have been..
Theoretically, disruption of fetal growth development could increase the risk of other health problems later in life. And a shorter waistline has been linked to a higher future risk of diseases such as heart disease and diabetes. But the authors did not find a clear link between coffee consumption and other early markers of these problems in these children, such as higher body weight. Other research, meanwhile, has not found a link between negative health outcomes during pregnancy and caffeine intake below 200 milligrams per day, and some research has even suggested that low doses of caffeine could reduce the risk of certain conditions such as gestational diabetes. And for the non-pregnant peoplemost searches keep on going to indicate that caffeine consumption is a net positive, at least in moderation.
The authors and outside experts acknowledge that further studies, including perhaps some that can similarly track outcomes in older children, will be necessary to know if the current caffeine recommendations for pregnant women should be modified.
“While the study results are interesting, further research is needed to support the conclusions and, as the researchers conclude, the clinical implication of this height difference is unclear and warrants future investigation,” Helena Gibson-Moore, a British Nutrition Foundation scientist not affiliated with the research, said that Ino statement provided by the Science Media Center.