New York – A new study – published in the JAMA Network Open – revealed, pregnant women taking more caffeine – even half a cup of coffee a day had slightly smaller babies than those who did not consume those beverages. It said corresponding reductions in size and lean body mass for infants whose mothers consumed below the 200 milligrams of caffeine per day, about two cups of coffee, believed to increase risks to the fetus. Researcher Katherine L. Grantz from the NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development, said: “Until we learn more, our results suggest it might be prudent to limit or forego caffeine-containing beverages during pregnancy.” The team analyzed data of over 2,000 racially and ethnically diverse women at 12 clinical sites who were enrolled from 8 to 13 weeks of pregnancy. Between weeks 10 to 13, pregnant women provided a blood sample that was later analyzed for caffeine and paraxanthine, a compound produced when caffeine is broken down in the body. Compared to infants born to women with no or minimal levels of caffeine, infants born to women who had the highest blood levels of caffeine were an average of 84 grams lighter at birth (about three ounces), were 0.44 centimeters shorter (about .17 inches), and had head circumferences 0.28 centimeters smaller (about 0.11 inches).