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.
All insulins, or metformin can be used in breastfeeding. There is limited or no published information on the use of other antidiabetic (blood-glucose lowering) medicines during breastfeeding. Contact us for advice about other antidiabetic medicines, or about using them for indications other than diabetes.
Management of diabetes
Insulin requirements may be less, and dosages of antidiabetic medicines may be different, than those needed during or before pregnancy since glucose is being used for milk production.
Effect on breastfeeding
It is important that diabetes is well treated while breastfeeding. Poorly controlled blood sugar levels can make it more difficult to get started with breastfeeding and can affect the amount of milk produced.
Any insulin can be used during breastfeeding, although monitoring is still recommended.
As a precaution, monitor the infant for signs of hypoglycaemia, including drowsiness, appearing pale, or being sweaty or shaky. Monitor for adequate weight gain.
Insulin is naturally found in breast milk and is essential for the healthy development of the infant. A small amount is absorbed by the infant and helps with intestinal maturation and induces glucose tolerance. It may also decrease the risk of developing type 1 diabetes.
Exogenous insulin is also excreted into breast milk, including that from insulin analogues. The amount that passes across into milk is unlikely to cause any side effects in the breastfed infant. The majority of exogenous insulin will be destroyed in the infant’s gastro-intestinal tract and will not be absorbed.
Metformin can be used during breastfeeding due to negligible amounts in breast milk. Monitoring is still recommended.
As a precaution, monitor the infant for vomiting, diarrhoea and signs of hypoglycaemia, including drowsiness, appearing pale, or being sweaty or shaky. Monitor for adequate weight gain.
Limited published evidence has found negligible amounts in breast milk.
No side effects have been reported in breastfed infants.
Patient information for insulins and other antidiabetic medicines is available from the NHS Website: Medicines A-Z, including their use in breastfeeding.
Get in touch with the UK Drugs In Lactation Advisory Service (UKDILAS), our specialist breastfeeding medicines advice service, if:
- the infant is premature or unwell
- multiple medicines are being taken
- the medicine in question is not included in our advice
- you need further advice.
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.
- Updated to include advice on metformin, and other antidiabetic medicines