There is often inconsistent advice provided to mothers about the safety of continuing to breastfeed when taking medications. Breastfeeding mothers can safely use most prescribed medications, however some medications within a class may be more preferred over others.

This guideline aims to provide guidance in relation to the use of medicines during breastfeeding and the resources available to assist medicine choice for breastfeeding women.

To promote breastfeeding-friendly medication prescribing at Ballarat Health Services.

To ensure a mother’s desire to breastfeed is respected and supported through choice of medications compatible with breastfeeding where possible.

To provide guidance to clinical staff in relation to the use of medications during breastfeeding.

To communicate a patient's breastfeeding status through the use of an alert sticker on all medication order forms.

FDA - USA Food and Drug Administration.

GIT - Gastrointestinal tract.

NSMC - National Standard Medication Chart.

PBS - Pharmaceutical Benefits Scheme.

Vd - Volume of distribution (the theoretical volume that the total amount of drug administered would have to occupy to produce the concentration in plasma).

All clinical staff involved in the medicine management pathway for breastfeeding women including medical and other authorised prescribers, lactation consultants, midwives, nursing staff, pharmacists and radiology staff.

It is universally agreed that human milk is best for human infants and it is rarely necessary for a mother to stop breastfeeding due to the need to take a medication. However, it is important to consider the risks and benefits of each medication, as well as the benefits associated with breastfeeding. Whilst medications do transfer into human milk to some extent, most don't enter breast milk in amounts that are hazardous to a breastfed infant.

Factors Affecting Medication Transfer Into Breast Milk:

Maternal plasma concentrations - drugs that reach high maternal plasma concentrations have a greater chance of transferring into breast milk.

Vd - medications with a high Vd are less likely to transfer into breast milk; medications with Vd 1-20 L/kg are usually considered compatible for breastfeeding.

Molecular weight - medications with high molecular weights (>800 Daltons) need to be actively transported or dissolve in the cells lipid membranes and are therefore less likely to enter breast milk.

Protein binding - the unbound (free) fraction of a medication is what transfers into breast milk and therefore drugs which are highly protein bound (such as warfarin and many NSAIDs) are less likely to transfer into breast milk.

Lipid solubility - highly lipid soluble medications are more likely to transfer into breast milk.

Route of administration - medications administered parentally enter breast milk more quickly and in higher amounts. For orally administered medications, those with low bioavailability will be less likely to transfer to the infant's plasma.

Timing of medication administration - maternal milk volume is usually highest in the early morning therefore medication administration at this time may result in higher concentration in breast milk. 

Stage of lactation - for medications to transfer into breast milk they need to pass through the maternal plasma compartment via capillaries into the lactocytes lining the alveolus. They then must penetrate through lipid membranes of the alveolus to pass into breast milk. During the first 72 hours postpartum there are large gaps between the alveolar cells, which allow access into the milk for most medications. Despite this, most medications produce subclinical amounts in the infant due to the limited milk volume at this time. After three days, these gaps close, reducing the transcellular entry of most medications.

Medications Contraindicated During Breastfeeding:

There are few medications that are contraindicated for use by breastfeeding mothers, these include (but are not limited to):

• Ergotamine derivatives (e.g. bromocriptine),

• Gold salts,

• Iodine,

• Radiopharmaceuticals (nuclear medicine scans),

• Chemotherapy,

• Codeine and codeine-containing preparations,

• Illegal/street drugs.

For pregnant and breastfeeding patients using illegal/street drugs the emphasis should be on providing support and assistance for the woman to stop using these substances. A risk assessment and harm minimisation approach should be taken including consideration of referral to the Women's Alcohol and Drug Service (WADS). Fast fax referral form available at: https://www.thewomens.org.au/health-professionals/maternity/womens-alcohol-and-drug-service/

BHS CPG0278 Alcohol And Other Drugs Use In Pregnancy And Breastfeeding is available to support healthcare professionals at Ballarat Health Services to provide consistent, evidence-based care, support and appropriate referrals for women who use alcohol and other drugs during the perinatal period.

In 2017, the FDA released a statement cautioning breastfeeding mothers to avoid tramadol as the drug is thought to pose the same risk as codeine. To date, the medical literature does not report adverse events associated with tramadol and breastfeeding.

For all women of child-bearing age, attending health professionals must determine if the patient is pregnant or breastfeeding and document in the progress notes. For those women who are breastfeeding, the 'Breastfeeding Mother' alert sticker (Appendix) should be used to highlight the patient's breastfeeding status as outlined below. The sticker is available on most wards. Contact ward 5 North, the Lactation Consultants or Pharmacy Department for additional supplies.

General Considerations For Prescribing Medications For Breastfeeding Women:

Avoid prescribing medications that are not necessary and consider non-drug treatments where possible.

Choose medications for which there is published safety data for use in breastfeeding, rather than newer medications with limited or no information.

Choose medications with short half-lives, high protein binding, low oral bioavailability, or high molecular weight (refer Issues to Consider).

Use with caution medications (or medications with active metabolites) that have long paediatric half-lives, such as benzodiazepines and barbiturates.

Choose the lowest dosage possible for the patient and avoid extra-strength and long-acting preparations where possible.

Evaluate the infant be more cautious with premature infants or neonates and very ill babies. Older infants can metabolise and eliminate medications more easily.

Medications used in the first three or four days post partum or in late stage lactation (after 1 year) generally produce subclinical levels in the infant due to the limited volume of milk ingested.

If possible schedule medication doses for administration just prior to a breastfeed or schedule breastfeeding for at least 2 hours after taking a dose to avoid peak drug concentrations in the breastmilk. Short acting medications taken on a 3 to 6 hourly schedule usually reach peak plasma and milk levels in approximately 1 to 2 hours.

In instances when a mother is advised to avoid breastfeeding for a period of time, it is important that she is provided with guidance on how to manage such periods e.g. referral to lactation consultant to assist with expressing and discarding.

Intravenous contrast and breastfeeding

Breastfeeding can continue as normal after receiving IV contrast due to the low bioavailability and small percentage excreted into the breast milk and absorbed by the infant. Breastmilk does not need to be expressed and discarded after administration of IV contrast.

Anaesthetics and breastfeeding

Mothers of full term or older infants can breastfeed after an anaesthetic as soon as they are awake, stable and alert. Most anaesthetic drugs enter breastmilk in only minimal amounts and will have cleared from the plasma and milk compartments by the time the mother is awake. This can be attributed to the short half-lives and poor oral bioavailability of most IV anaesthetic agents and therefore expressing and discarding breastmilk after an anaesthetic is generally not necessary.

Some caution is required if the mother is breastfeeding a baby who is preterm and/or experiencing apnoea or hypotension. In this situation expressing and discarding breastmilk for 12-24 hours may be recommended. For more information regarding anaesthetic use in breastfeeding, the below resources can be used.  

 References and Resources For Further Information:

During business hours, consult in person with:

BHS pharmacy department page the clinical pharmacist rostered to the unit or for clinical areas without a clinical pharmacy service complete a BOSSNet referral or phone x 94113 to speak to a pharmacist immediately during pharmacy opening hours (Monday - Friday 8.30am - 5.30pm, Saturday - Sunday 10am - 12 noon). A weekend a public holiday clinical pharmacy service is available from 8.30am - 5pm via pager 5792.

BHS Clinical Midwife Consultant (Lactation) - contact via mobile phone 0439 981 937 (Monday - Friday 8am - 4.30pm)

Maternity Unit (5 North)

BHS Obstetrics and Gynaecology Medical team

BHS Paediatric Medical team

Medicines Information Service - the following external services offer specialist information regarding medicines and breastfeeding:

Royal Womens Hospital phone: 03 8345 3190 (Monday - Friday 9am - 5pm)

Monash Health phone: 03 9594 2361 (Monday - Friday 9am - 5pm)

After hours consult with the following:

In person: Maternity Unit (5 North) or BHS Obstetrics and Gynaecology or Paediatric Medical teams

Online references/resources:

The manufacturers product information (e.g. MIMS) provides limited information about the safety of medicines during breastfeeding; always consult a second source for further clarification. Available via BHS library intranet

The Royal Womens Hospital Pregnancy and Breastfeeding Medicines guide is a quick reference guide for health professionals that provides practical and unbiased specialised information on medicine use during pregnancy and breastfeeding and is regularly updated. Available via BHS library intranet https://thewomenspbmg.org.au.acs.hcn.com.au/?acc=36265

LactMed is an American peer-reviewed free online database with information on over 450 medications. It includes information such as maternal levels in breast milk, serum levels in infants, potential effects on breastfeeding infants and on lactation itself, the American Academy of Pediatrics category indicating the level of compatibility of the medication with breastfeeding, and alternate drugs to consider. References are included. LactMed is regularly updated and continues to expand.

Available at: http://toxnet.nlm.nih.gov/newtoxnet/lactmed.htm

WHO Breastfeeding and Maternal Medication (2002) has been developed to help the health worker decide whether a mother who is breastfeeding and who needs treatment with drugs can take the necessary medication and still continue breastfeeding safely. Information is provided about specific drugs following the Eleventh Model List of Essential Drugs. The document includes a guide on how to use the list as well as information on how the medications are classified for breastfeeding.

Available at: http://www.who.int/maternal_child_adolescent/documents/55732/en/

Reference Text Books: the Special Care Nursery and Maternity Unit (5 North) have a number of hard copy specialist reference texts on medications and breastfeeding which can be consulted for after hours advice.