Drugs in Pregnancy

The Therapeutic Goods Administration classifies drugs for suitability in pregnancy based on the potential of a drug to cause:

  • Birth defects
  • Detrimental effects at birth
  • Problems in later life

The classification system is:

  • Valid only for the dose and route of administration listed
    • Does not apply in overdose
  • Not hierarchical
    • 'B' drugs are not safer than 'C' drugs


  • Category A
    Taken by large number of women without detrimental effects.
  • Category B
    Taken by a limited number of women without detrimental effect. Subclassified by results from animal studies into:
    • Category B1
      Animal studies show no evidence of detrimental effect to the foetus.
    • Category B2
      Animal studies are inadequate or lacking, but available data shows no evidence of detrimental effect to the foetus.
    • Category B3
      Animal studies show evidence of foetal damage, but the significance of this in humans is unknown.
  • Category C
    • Drugs which have caused (or a suspected to cause) detrimental foetal effects, but without malformations
    • These effects may be reversible
  • Category D
    • Drugs which have caused (or are suspected to cause) an increased incidence of foetal malformations or damage
    • May also have detrimental effects
  • Category X
    • Drugs which have a high risk of causing permanent damage
    • Should not be used in pregnancy, or when pregnancy is possible


  1. Australian categorisation system for prescribing medicines in pregnancy. Therapeutic Goods Administration.
Last updated 2019-11-30

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