Pregnancy medicines guide
Medicines in pregnancy: what do the safety categories mean?
By Patrick LeachPublisher: HerDoc
Pregnancy safety categories explain what the available evidence tells us about a medicine’s potential risks to an unborn baby. In Australia, the categories are A, B1, B2, B3, C, D and X. They help inform treatment decisions, but aren’t a simple ranking from safest to least safe. Your GP or pharmacist can explain what a category means for your medicine and circumstances. TGA guidance.
Finding a letter beside a medicine you take can leave you with more questions than answers. Does B3 mean something is wrong? Should you be looking for an alternative? What if you took it before knowing you were pregnant?
Understanding the categories can make that conversation easier.
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What do the Australian pregnancy categories mean?
The categories describe different kinds of evidence and potential harm:
| Category | Meaning |
|---|---|
| A | Extensive human use has not shown increased birth defects or other fetal harm. |
| B1, B2 and B3 | Limited human use has not shown increased harm. Animal evidence differs: B1 shows no increased fetal damage; B2 is inadequate or missing, with available evidence showing no increase; B3 shows fetal damage whose relevance to humans is uncertain. |
| C | May cause harmful effects, potentially reversible, without causing birth defects. |
| D | Known or suspected risk of birth defects or irreversible damage; use is not always ruled out. |
| X | High risk of permanent fetal harm; must not be used during pregnancy or when pregnancy is possible. |
These summaries follow the TGA’s Australian category definitions. Category B does not necessarily mean safer than category C.
How does the category help with a decision about your medicine?
Your care team can explain the benefits of treatment, possible risks and available alternatives. The aim is to find an approach that looks after both you and your baby.
That conversation matters for medicines bought at a pharmacy or supermarket as well as prescriptions. The Royal Women’s Hospital recommends checking with a doctor or pharmacist before taking an over-the-counter medicine during pregnancy.
A category is also only part of the information available. The TGA database includes accompanying safety statements, and the regulator says even health professionals should not use it as their sole or main prescribing resource. It is intended to support professional decisions, rather than act as a personal medicine checker. About the TGA database.
What changed in October 2026?
On 21 October, the TGA added 13 medicines to its pregnancy database and amended one existing category.
The update is a useful reminder to check current information. It is not a general instruction to change treatment, and the announcement does not establish that a medicine is suitable for every pregnant person.
What if you took a medicine before knowing you were pregnant?
You can get advice about the specific medicine and what to do next. Contact your GP or pharmacist promptly, with the packet or a photo of the label handy. Note how much you took, when you took it and roughly how far along your pregnancy may be.
Avoid making a decision from the category alone. Suddenly stopping a prescribed medicine can also be harmful. If you discover you are pregnant while taking regular treatment, speak with your prescriber as soon as possible so you can agree on a plan. Guidance on medicines and an unplanned pregnancy.
If you already know the medicine must not be used during pregnancy, seek urgent advice from your prescriber or pharmacist about the exposure and your next dose.
What should you ask your GP or pharmacist?
You do not need to interpret the evidence yourself before asking for help. Have a list of your prescriptions, occasional medicines, vitamins and herbal products ready.
Useful questions include:
- What does this category mean for the medicine I take?
- What is known about its use in pregnancy, and what remains uncertain?
- What are the benefits and risks of continuing treatment?
- Are there alternatives worth considering?
- Do I need any changes or follow-up, and when should we review the plan?
If you are planning a pregnancy, arranging this conversation beforehand gives you and your GP time to plan your ongoing care. Pre-pregnancy medicine advice.
You deserve an explanation that goes beyond a letter—one that helps you understand your options and feel involved in the next step.