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.
Recommendations
Warfarin is the preferred oral anticoagulant to use during breastfeeding due to wider experience and no reported infant side effects.
There is less published evidence for direct oral anticoagulants (DOACs). Dabigatran or rivaroxaban can be used if clinically indicated based on passage into breast milk, the amount likely to be absorbed by the infant and the availability of published evidence.
Treatment choice should primarily be directed at controlling symptoms, with safety in breastfeeding a secondary consideration.
See also our guidance on heparins in breastfeeding.
Specific recommendations
Warfarin
Preferred choice
Warfarin can be used during breastfeeding, although infant monitoring is required.
Infant monitoring
As a precaution, monitor the infant for bruising on the skin, blood in urine, vomit, or stools.
Monitoring the infant will quickly pick up any potential issues but usually further investigation is required before the cause can be attributed to the medicine.
Further information
There is a moderate amount of published evidence of use during breastfeeding. Warfarin is highly protein bound and negligible amounts pass into breast milk (0.01% of the weight-adjusted maternal dose). Plasma levels of warfarin were undetectable in infants exposed to warfarin via breast milk.
No side effects have been reported in breastfed infants who have been exposed. Even in a case of accidental maternal overdosing, the breastfed infant did not show any clinical problems and coagulation tests were not altered.
Direct Oral Anticoagulants (DOACs)
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 is now increasingly being used due to the ethical difficulties around gathering good quality evidence in this area.
Bibliography
Full referencing is available on request.
Update history
- Full clinical update and rewrite
- Minor title amendment
- Published