Pregnancy Risk Categories (FDA Definitions)

Pregnancy Risk Categories (FDA Definitions)

Category A: Adequate, well-controlled studies in pregnant women have not shown an increased risk of fetal abnormalities.

Category B: (1) Animal studies show no adverse fetal effects, but there are no controlled human studies, or (2) animal studies show adverse fetal effects, but well-controlled human studies do not.

Category C: (1) Animal studies show adverse fetal effects, but there are no controlled human studies, or (2) no animal or wellcontrolled human studies have been conducted.

Category D:Well-controlled or observational human studies show positive evidence of human fetal risk. Maternal benefit may outweigh fetal risk in serious or life-threatening situations.

Category X: ContraindicatedWell-controlled or observational human and/or animal studies show positive evidence of serious fetal abnormalities. Fetal risks far outweigh maternal benefit.