Nov. 1, 2022 -- Children who were exposed to small amounts of caffeine in utero were shorter on average than those who were not, says a new study published in JAMA Network Open.

“The reductions were apparent even with levels of caffeine consumption below clinically recommended guidelines of less than 200 mg per day,” the authors wrote. “The clinical implication of this height difference is unclear and warrants future investigation.”

The slightly lower sizes were recorded starting at age 4 and increased through age 8, “translating to a 0.68 to 2.2 cm difference,” the study says.

“To be clear, these are not huge differences in height, but there are these small differences in height among the children of people who consumed caffeine during pregnancy,” lead author Jessica L. Gleason, PhD, a perinatal epidemiologist, told CNN.

Pregnant women should consume no more than 200mg of caffeine a day, the American Academy of Obstetricians and Gynecologists says.

A mug of filtered coffee has about 140mg. Caffeine is also found in tea, soft drinks, energy drinks, cocoa, and chocolate.

The differences found in the study showed up in kids whose mothers drank less than half a cup of coffee per day while pregnant, Gleason said.

It’s unclear if this would result in ongoing height differences into adulthood. And the study did not establish a causal link between higher caffeine consumption and shorter stature.

“Shorter stature, though not necessarily associated with obesity in childhood, has been associated with obesity and increased diabetes risk in adults,” the study says.

Show Sources

JAMA Network Open: “Association of Maternal Caffeine Consumption During Pregnancy With Child Growth”

CNN: “Even less than recommended amounts of caffeine while pregnant could impact your child’s life”

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