The questions asked should provide information on factors that are critical to the risk assessment for each individual pregnancy.

Identifying risk factors

You should first read our advice on the risk considerations and principles of prescribing during pregnancy.

The risks and principles of prescribing in pregnancy

Prescribing in pregnancy requires balancing maternal and fetal risks. This guidance outlines key risks and principles to ensure safe, informed decisions.

Informing risk versus benefit assessment 

When prescribing for a pregnant woman, it’s important to weigh the potential harm to the fetus from the medicine against the risks of not treating the mother’s condition.

Risk assessment is challenging due to limited data available on the use of medicines during pregnancy. It is not possible to create definitive lists of ‘safe’ or ‘unsafe’ medicines as each case must be considered individually. A woman may view risks differently during pregnancy than she might otherwise, making personalised, shared decision making important.

It is worth checking if a risk assessment has already been completed by the specialist team. The ideal scenario is to complete a risk assessment in advance of any pregnancy so that mitigating actions may be considered. 

Pregnancy is unique in that two individuals, the mother and fetus are exposed, with risks and benefits for each. The maternal benefits and risks of a medicine in pregnancy are not necessarily the same as for non-pregnant women. This is due to altered physiology and pharmacology which may affect the efficacy of the treatment, or the risk of adverse effects. 

Gather information

Take a stepwise approach to gathering information for the use of medicines during pregnancy. This will help you identify whether the medicine is suitable. You might not be able to get all this information, but it is important to get as much as possible.

Look at the evidence

Know where to go for reliable pregnancy resources.

See our advice on information resources.

Complete the risk assessment

Evaluate the evidence alongside the information you have gathered about the mother and medicine. Consider at minimum the following factors:

Scientific considerations

  • Does the available evidence for use of the medicine in pregnancy suggest an increased risk of congenital anomaly?
  • At what stage of pregnancy is exposure to the medicine associated with an increased risk?

Clinical considerations

  • What is the indication for the medicine and is it really needed?
  • Is the medicine being used to treat a minor or serious condition?
  • Are there treatment alternatives about which more is known or which pose a lower risk?
  • What is the risk to the mother if ongoing treatment is to be paused or stopped?
  • Will the medicine also be appropriate should the mother want to breastfeed?
  • Is there an alternative route or formulation which lowers risk? For example, would topical eye drops and nasal spray be effective for hay fever symptoms in preference to an oral antihistamine.

Patient circumstances

  • At what stage of pregnancy is the patient?
  • Is the patient’s condition well controlled on the medicine?
  • Does the patient have concomitant illness?
  • Has the patient got an increased risk of adverse pregnancy outcome based on other risk factors such as her age or obstetric history?

Timing of the risk assessment

If a woman is pregnant but is not yet using the medicine(s), the pharmacist or health care professional should provide advice on:

  • Choice or change of therapy
  • Potential risk of adverse effects or toxicity to the fetus (fetotoxicity)
  • Risk reduction, for example, stopping treatment if clinically possible or appropriate

Assessment after either inadvertent or deliberate medicine or chemical exposure during pregnancy, can require more careful, sensitive and nuanced advice. This may include the following actions:

  • Continue, or stop treatment or exposure
  • Give reassurance
  • Prenatal diagnostic tests
  • Genetic counselling
  • In the case of acute poisoning – advice on treatment of the mother and potential risks to the mother and fetus
  • Consider therapeutic abortion – specialist advice must be sought before this is discussed or considered.

Make a decision

Use all the information gathered to reach an informed conclusion using a shared decision making approach.

The risk assessment will enable you to provide advice that informs the decision about the use of a medicine for that individual. This will include whether there need to be any additional options to reduce the risk and what infant monitoring might be required.

Sometimes it may be necessary to prescribe a medicine known or suspected of increasing the risk of birth defects and developmental disorders (a teratogen). This can happen when the potential benefits outweigh the risks, such as in cases of severe maternal illness or advanced stages of pregnancy.

Seek further advice

Seek expert advice whenever there is any doubt about the safety of a medicine in pregnancy. If the information is not available on the SPS website, or your clinical scenario is complex, we would suggest you seek further advice. If you work in primary care, you can contact the Medicines Advice Service.

Update history

  1. Full review and update. Title of the article changed from 'Questions to ask when giving advice on medicines in pregnancy' to 'Conducting a medicines risk assessment in pregnancy'.
  2. Published

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