FDA Class use in pregnancy ratings where there where controlled studies showing no risk
Category A
FDA Class use in pregnancy ratings where there where no evidence of risk in humans and no adverse animal findings
Cat B
FDA Class use in pregnancy ratings where there where risk cannot be ruled out
Cat C
FDA Class use in pregnancy ratings where there where there is a positive evidence of risk
Cat D
FDA Class use in pregnancy ratings where there where where the med is contraindicated in pregnancy
Cat X