Caffeine Increases Risk of Miscarriage, Study Finds

Women who consume as little as half a cup of coffee a day right before or during pregnancy may increase their risk of miscarriage, says a new study that adds to the conflicting data available about caffeine.

Since 1980, the Food and Drug Administration has recommended that pregnant women cut down on caffeine, authors of the new study noted. That recommendation was based on animal studies, but most doctors probably advise their patients along those lines, said the authors, led by Dr. Claire Infante-Rivard of McGill University in Montreal.

They compared 331 women who had miscarried with 993 who had experienced normal pregnancies and reported their findings in today’s issue of the Journal of the American Medical Assn.

The researchers found that consuming as little as 48 milligrams of caffeine--about the amount in half a cup of coffee--a day during the month before conceiving boosted miscarriage risk by 29%. Consuming the same amount during pregnancy boosted the risk by 15%.

Each additional 100 milligrams of caffeine daily boosted the risk by another 22%, the researchers said. That is about the amount of caffeine in eight ounces of coffee, 15 ounces of tea or eight to 15 ounces of soft drinks containing caffeine. It also is found in many over-the-counter pain remedies.

“A reasonable recommendation would be to reduce consumption of caffeine beverages during pregnancy,” the researchers said. They stopped short of recommending that women go cold turkey.

The study comes 10 months after federal researchers reported that expectant mothers who consumed up to 300 milligrams of caffeine daily had no higher rates of miscarriage or small fetuses than non-consumers of caffeine.

Richard P. Leavitt, director of science information for the March of Dimes, which was not involved in the study, said: “Any drug that crosses the placenta, as caffeine does, may be regarded as possibly hazardous, especially during the first three months of pregnancy.”

Women who want “complete peace of mind about the possible hazards of caffeine” should avoid it, the March of Dimes said.