FDA Pregnancy Classifications

- FDA Pregnancy Classifications Category Description A Controlled studies showed no demonstrated risk to the fetus in the first trimester, or later trimesters during pregnancy. B Studies on pregnant animals showed no demonstrated risk to the fetus, but controlled studies on pregnant women were not conducted. C Studies on pregnant animals showed adverse effect on fetus, but controlled studies on pregnant women were not conducted. In some instances, the potential benefit for the use of drugs in this category may outweigh the potential risks for the pregnant mother. D Investigational or marketing studies show a positive evidence of fetal risk in humans. However, again, the potential benefits may outweigh the potential risk for the pregnant mother. X Investigational or marketing studies show demonstrated fetal abnormalities and evidence of fetal risk because of adverse reactions. Risk of use in this category outweighs the potential benefits. N There is no FDA classification on these drugs.