Pregnancy category of drugs are an assessment of the risk of fetal injury due to the drug, if it is used as directed by the mother during pregnancy. It does NOT include any risks of drugs or their metabolites in breast milk.

• Pregnancy category A, whihc have been taken by a large number of pregnancy women and women of childbearing age WITHOUT an increase in frequency of malformations, or other direct or indirect harmfule ffects, on the fetus having been observed
• Pregnancy category B1, which have been taken by only a LIMITED number of pregnancy women and women of childbearing age, WITHOUT an increase in the frequency of malformation or other direct or indirect harmful effects, on the human fetus having been observed. Studies in animals have NOT shown evidence of an increased occurence of fetal damage
• Pregnancy category B2, which have been taken by only a LIMITED number of pregnanty women and women of childbearing age, WITHOUT an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals are INADEQUATE or may be lacking, but available data shows NO EVIDENCE of an increased occurence of fetal damage
• Pregnancy category B3, which have been taken only by a LIMITED number of pregnant women and women of childbearing age, WITHOUT an increase in the frequency of malformation or other direct or indirect harmful effects on the human fetus having been observed. Studies in animals HAVE shown evidence of an increased occurence of fetal damage, the singificance of which is considered uncertain in humans
• Pregnancy category C, which owing to their drug effects, HAVE caused or may be suspected of causing, harmful effects on the human fetus or neonate without causing malformations. These effects may be REVERSIBLE
• Pregnancy category D, which have caused, are suspected to HAVE caused, or may be expected to cause, an increased incidence of human fetal malformations or IRREVERSIBLE damage. These drugs may also have adverse drug effects
• Pregnancy category X, which hve such a high risk of causing permanent damage to the fetus that they should NOT be used in pregnancy or when there is a possibilty of pregnancy