Antiplatelets can be used with caution in breastfeeding. Avoid exposure to aspirin if infant has a fever. Recommendations apply to full term, healthy infants.

General considerations

It is important to complete an individual risk assessment for your patient and to apply the principles of prescribing in breastfeeding when looking at the available information and making treatment decisions.


There is little or no published evidence on the use of antiplatelet medicines during breastfeeding.

Limited published information on low-dose aspirin (defined here as 75mg to 150mg daily) shows milk levels are negligible.

However the pharmacokinetic parameters of all antiplatelet medicines suggest all are likely to pass into breast milk in low amounts and any antiplatelet medicine can be used with caution during breastfeeding.

There is insufficient information to recommend a preferred agent.

Choice considerations

Choice of antiplatelet medicines in breastfeeding will be dependent on a number of factors, including patient-specific characteristics, clinical condition and patient preference.

More than one antiplatelet medicine may need to be used in combination and therefore their additive suitability in breastfeeding will need to be considered.

Several antiplatelet medicines require a loading dose when starting treatment.  There is limited or no information on higher doses for short durations and enhanced infant monitoring is recommended if breastfeeding is maintained through any acute illness.

Treatment choice should primarily be directed at managing the clinical condition, with safety in breastfeeding a secondary consideration.

Breastfeeding itself can also help to reduce the risk of cardiovascular disease.

Aspirin and the risk of Reye’s syndrome

Reye’s syndrome is a disorder characterised by acute encephalopathy and fatty degeneration of the liver.  The exact cause is unknown- but it most commonly affects children and young adults recovering from a viral infection.

Aspirin has been associated with Reye’s syndrome when administered to children with a fever.  It is unknown whether the negligible amounts of aspirin present in breast milk following an antiplatelet dose could cause Reye’s syndrome in a breastfed infant.

To minimise the risk, if the infant has symptoms of a viral infection or fever, consider temporarily discontinuing the aspirin if clinically justified, or temporarily withholding breast milk.

Specific recommendations

Patient Information

The NHS website provides advice for patients on the use of specific medicines in breastfeeding.

Contact us

Get in touch with the UK Drugs In Lactation Advisory Service (UKDILAS), our specialist breastfeeding medicines advice service if you need support in the following situations:

  • you need further advice
  • the medicine in question is not included here
  • the infant is unwell or premature
  • multiple medicines are being taken

About our recommendations

Recommendations are based on published evidence where available. However, evidence is generally very poor and limited, and can require professional interpretation. Assessments are often based on reviewing case reports which can be conflicting and lack detail.

If there is no published clinical evidence, assessments are based on: pharmacodynamic and pharmacokinetic principles, extrapolation from similar drugs, risk assessment of normal clinical use, expert advice, and unpublished data. Simulated data are now increasingly being used due to the ethical difficulties around gathering good quality evidence in this area.


Full referencing is available on request.

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