Too Much Caffeine May Lead to Smaller Babies

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The Scoop

Trying to cut back on caffeine? A new study on the health effects of drinking too much caffeine during pregnancy may just give you the motivation you need to skip that extra cup of coffee or bottle of soda. Published in the June 2010 issue of the American Journal of Clinical Nutrition, the study from researchers in the Netherlands tracked caffeine consumption among more than 7,300 women from early pregnancy onward.

According to researchers, between 2 and 3 percent of women said they consumed the caffeine equivalent of six cups of coffee per day. Compared to mothers who consumed less caffeine during pregnancy, researchers noted that babies born to heavy caffeine consumers were slightly shorter, on average, at birth and during all three trimesters of fetal development, based on ultrasound tests. Heavy caffeine consumers also had an increased risk of having a baby who was small for gestational age.

"Caffeine intake seems to affect length growth of the fetus from the first trimester onwards," says lead researcher Rachel Bakker, in an interview with Reuters Health.

Bakker also speculated that while the study seemed to show that pregnant women should not consume more than six cups of coffee per day, the findings did not necessarily mean that less coffee should be viewed as "safe" during pregnancy.

"We only studied the effect of caffeine on fetal growth," the researcher tells Reuters. "Future studies on possible other effects of maternal caffeine intake are therefore needed."

For Baby

Studies about caffeine and pregnancy have produced conflicting results. According to Reuters Health, some studies link regular caffeine consumption during pregnancy—even a relatively modest one or two cups of coffee a day—to an increased risk of low birth weight. But other studies have found no such effects. To be on the safe side, prenatal health experts at the March of Dimes generally recommend that pregnant women limit their intake to no more than 200 milligrams of caffeine per day—roughly the amount in one 12-ounce cup of coffee.