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Group Cites Increased Risk of Miscarriage, Childhood Leukemia

November 19, 2014

The federal government may be poised to give women who are or might become pregnant bad advice on how much caffeine is safe to consume during pregnancy, according to the Center for Science in the Public Interest. Draft advice from the government's Dietary Guidelines Advisory Committee indicates that pregnant women should be sure to limit their caffeine consumption to 200 milligrams per day. But CSPI says following that advice could increase the risk of adverse pregnancy outcomes, including spontaneous abortion, stillbirth, preterm delivery, and childhood leukemia.

The nonprofit group says that the Dietary Guidelines Advisory Committee, which every five years crafts the government's official nutrition advice, should instead advise pregnant women to avoid caffeine-containing foods and beverages. In comments filed today CSPI pointed to a recent meta-analysis published in the European Journal of Epidemiology which found that a dose as low as 100 mg per day of caffeine was associated with a 14 percent increase in risk of miscarriage, and a 19 percent increase in the risk of stillbirth. Consumption of 100 mg of caffeine per day was also associated with increased risks of small-for-gestational-age fetuses and low birth weight. Risks increase as caffeine dosages increase, according to the study.

To put 100 mg of caffeine into context, a 16-ounce Grande Starbucks coffee has 330 mg of caffeine. Coffee you brew at home has between 60-150 mg per 5-ounce cup, depending on how it is brewed. A 20-ounce bottle of Diet Coke has 78 mg.

"Pregnant women deserve accurate advice about the risks caffeine poses to their healthy pregnancy and have been badly misinformed," said CSPI chief regulatory affairs attorney Laura MacCleery. "The Dietary Guidelines for Americans shouldn’t compound this problem by conveying an impression that 200 milligrams per day is some kind of red line below which caffeine is safe and above which caffeine is dangerous. Instead, the science indicates that even lower levels of caffeine can increase the risk of serious problems, including for only a cup or two of regular coffee per day."

CSPI's comments indicate flaws in the advice given to pregnant women by the respected American College of Obstetricians and Gynecologists, which the Dietary Guidelines Advisory Committee cites in its draft recommendation. ACOG's analysis of the risk of miscarriage posed by caffeine is thin and outdated, the group says. While the recent meta-analysis considers 25 separate studies, ACOG considered only two of those, including the lone study that found no link to an increased risk of miscarriage.

The Food and Drug Administration used to recommend that pregnant women avoid caffeinated drinks altogether, or consume them only sparingly. "As a general rule, pregnant women should avoid substances that have drug-like effects and can cross the placenta," the agency wrote in a 1981 brochure.

CSPI's comments also call on the DGAC to consider the risk of childhood leukemia related to drinking coffee during pregnancy. A 2014 meta-analysis published in the American Journal of Obstetrics and Gynecology found a dose-related increased risk of childhood acute leukemia associated with maternal coffee consumption. In comments to the DGAC, epidemiologist Peter Infante called the evidence linking maternal coffee consumption during pregnancy and childhood acute leukemia "strong." In the U.S., lifetime probability of childhood acute leukemia in children aged 0 to 14 is approximately 73 per 100,000. According to a risk analysis submitted to the DGAC by biostatistician Steven Bayard, 19 of those cases might be attributable to coffee consumption of one to two cups per day during pregnancy.

The Dietary Guidelines Advisory Committee meets next on December 15.