Pregnant women who drink even small amounts of caffeine before giving birth tend to have babies who turn out to be shorter as children. In a new study published in the journal JAMA Network Open, researchers at the National Institute of Child Health and Human Development found that children of mothers who consumed caffeine during pregnancy were shorter at age 4 than the children whose mothers did not consume caffeinated beverages and foods. This gap in height increased every year until age 8. The American College of Obstetricians and Gynecologists recommends keeping caffeine consumption under 200 milligrams per day while pregnant, or between one and two cups of coffee. But in this study, as little as half a cup of coffee each day led to shorter children.