Caffeine half-life increases in pregnancy from 3 hours in the first trimester to 80 to 100 hours in late pregnancy. Women who are pregnant or trying to become pregnant are advised by the American College of Obstetricians and Gynecologists
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to consume no more than 200 mg of caffeine per day—the approximate amount in one 12-oz cup of coffee. However, birth defects research indicates moderate or high amounts of beverages and foods containing caffeine do not increase the risk of congenital malformations, miscarriage, preterm birth, or growth retardation.
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