Home » Fact Sheet

Category Archives: Fact Sheet

Opioids and breastfeeding

When paracetamol plus a non steroidal drug (ibuprofen, naproxen, diclofenac or celecoxib) are insufficient to control pain opioid drugs may need to be used. They cause constipation so should be co prescribed with a stool softener). They are also addictive so should be used for the shortest possible time, in the lowest possible dose.

Codeine is not recomemnded for breastfeeding https://breastfeeding-and-medication.co.uk/thoughts/breastfeeding-and-codeine but one accidental dose or short term use, maybe overnight when no other pain relief is available does not mean that breastfeeding needs to be interrupted.

No breastfeeding mother should ever be asked to choose between adequate pain relief and breastfeeding

Opioids and breastfeeding factsheet

Mirtazapine and breastfeeding

Another medication used during breastfeeding for anxiety and depression is mirtazapine. It may be used where other SSRIs have not been effective or tolerated. Mirtazapine may be also be seen as an option where insomnia is a symptom of  anxiety or depression.

The baby should be observed for signs of drowsiness and ineffective feeding.

Care should be taken with co sleeping because it is likely to cause drowsiness in the lactating mother. Falling asleep in chairs or on sofas should be regarded as an even greater risk https://www.basisonline.org.uk/

LactMed summarises that “Limited information indicates that maternal doses of up to 120 mg daily produce low levels in milk and would not be expected to cause any adverse effects in breastfed infants, especially if the infant is older than 2 months.” In practice the normal dose is 15mg taken at night.

Professionals may find the RCGP Perinatal mental health toolkit a useful resource https://www.rcgp.org.uk/clinical-and-research/resources/toolkits/perinatal-mental-health-toolkit.aspx

See also https://www.sps.nhs.uk/articles/using-duloxetine-mirtazapine-trazodone-or-venlafaxine-during-breastfeeding

The information in this factsheet is taken from my book Breastfeeding and Medication. Please message me with queries or the references used. wendy@breastfeeding-and-medication.co.uk

Mirtazapine and Breastfeeding Factsheet

Rivaroxaban and other anticoagulants and breastfeeding

For many years the standard anti coagulants to treat and prevent deep vein thrombosis (DVT) have been heparin and low molecular weight heparionoids e.g Enoxaparin (Clexane®)  or alternately but generally less frequently Tinzaparin (Innohep®), Dalteparin (Fragmin®, Fondaparinux (Arixtra®). Alternatively warfarin may be given as a tablet but generally takes too long to stabilise the clotting mechanism. All of these drugs are compatible with breastfeeding. The sub cutaneous injections are too large molecules which cannot be absorbed from breastmilk (are not orally bio-available). Because of the very low milk levels with warfarin doses less than 12 mg daily, amounts ingested by the infant are small. No adverse reactions in breastfed infants have been reported from maternal warfarin use during lactation, even with a dose of 25 mg daily for 7 days. There is a consensus that maternal warfarin therapy during breastfeeding poses little risk to the breastfed infant. No special precautions are necessary. (Lactmed https://www.ncbi.nlm.nih.gov/books/NBK501137/).

Although these drugs are not absorbed from milk, caution is recommended where there is donation to a milk bank of surplus breastmilk. Should any small amount reach a pre-term baby it may result in a bleed with catastrophic results. There are no studies to confirm this but the recommendation is made to protect these most vulnerable babies.

Deep vein thrombosis

Whilst DVTs are uncommon they are 5 times more common in pregnancy and in the first 6 weeks after delivery than in women who are not pregnant.

The risk of developing DVT during pregnancy is even greater if :

  • there is a history or family history of DVT
  • age over 35
  • obese BMI >30
  • a severe infection or recent serious injury, which restrict exercise
  • thrombophilia
  • multiple birth
  • after fertility treatment
  • after a caesarean section
  • currently smoke
  • have severe varicose veins
  • dehydration


If the clot breaks off into the bloodstream, it can block a blood vessel in the lungs. This is called a pulmonary embolism (PE) and needs emergency treatment. It may be investigated by a VQ or CT scan (preferably the latter as it involves no interruption of breastfeeding . See https://breastfeeding-and-medication.co.uk/fact-sheet/breastfeeding-after-vq-scans

The newer treatments to prevent clots are called Direct Oral Anticoagulant Medications (DOAC) which have advantages in that they are oral medications and need less frequent blood tests to confirm the INR.

UKDILAS have produced an excellent summary https://www.sps.nhs.uk/articles/using-oral-anticoagulants-in-breastfeeding-women/

Rivaroxaban  (Xarelto®): compatible with breastfeeding

  • Doses from breastmilk are over 100 times lower than doses given directly to pediatric patients. (Hale).
  • Several case reports consistently indicate that maternal doses of rivaroxaban of 15 to 30 mg daily produce low levels in milk that are considerably below doses required for anticoagulation in infants (Lactmed https://www.ncbi.nlm.nih.gov/books/NBK500742/.
  • Its pharmacokinetic data (large volume of distribution and high percentage of protein binding) explain the very small passage to milk observed in four different cases (Zhao 2020, Muysson 2019, Saito 2019, Wiesen 2016). https://www.e-lactancia.org/breastfeeding/rivaroxaban/product/
  • This is one of the preferred choice DOACs. Milk levels are low. Although rivaroxaban has a high oral bioavailability, very low levels are expected in milk due to its other pharmacokinetic properties, so infant exposure should still be minimal. https://www.sps.nhs.uk/articles/using-oral-anticoagulants-during-breastfeeding/

Dabigatran (Pradaxa ®) compatible with breastfeeding

  • There are no studies on the transfer of dabigatran to breast milk. The molecular weight is large (628 Daltons) and the oral bioavailability is low (6.5%); therefore, clinically relevant levels are not expected to occur in a breastfed infant. (Hale).
  • In adults, less than 7% of dabigatran is absorbed orally in its prodrug form of dabigatran etexilate mesylate; dabigatran itself is not absorbed orally. Preliminary data from 2 individuals indicate that dabigatran is poorly excreted into breastmilk and unlikely to affect the breastfed infant. If the mother requires dabigatran, it is not a reason to discontinue breastfeeding. Because data are limited, monitor preterm or newborn infants for signs of bleeding. (Lactmed https://www.ncbi.nlm.nih.gov/books/NBK500744/
  • Its low oral bioavailability (EMA 2018, Blech 2008) hinders transfer to infant plasma via breastmilk, except in premature infants and the immediate neonatal period when there may be increased intestinal permeability.It is the oral anticoagulant with the lowest excretion in breast milk (Daei 2021). https://www.e-lactancia.org/breastfeeding/dabigatran-etexilate/product/
  • This is one of the preferred choice DOACs. Milk levels are likely to be low. Dabigatran etexilate is one of the largest of the DOAC molecules and has a large volume of distribution, therefore it would be expected to pass into breast milk in low amounts. Milk levels were tested from two breastfeeding women who took dabigatran etexilate 220mg as a single dose. The relative infant dose was calculated to be between 0.01 and 0.07%. The infants did not receive any breast milk during this time. Infant absorption is likely to be low. Dabigatran etexilate also has very low oral bioavailability, so the infant is unlikely to absorb clinically significant amounts from the breast milk. It is therefore very unlikely that the infant would get any side-effects.https://www.sps.nhs.uk/articles/using-oral-anticoagulants-during-breastfeeding/

Apixaban(Eliquis®) and Edoxaban (Lixiana®) due to limited research should not be prescribed during breastfeeding.

Topical preparations and breastfeeding

There are so many reasons that we need to apply creams, lotions, ointments and pastes to our bodies when breastfeeding. There is poor absorption of most products applied topically and most can be used without interrupting breastfeeding. These include:

  • Moisturizers/emollients used to soothe skin e.g Diprobase ® , Dermol ® , E45 ® , Aveeno ® , Cetraben
  • Topical steroids to soothe eczema should be applied sparingly regardless of breastfeeding and accompanied by emollients to keep skin supple eg Betnovate ®, Eumovate ® , Elocon ® , Hydrocortisone. They can be applied to the nipple very sparingly for short periods of time after feeds without needing to wash off as this may further damage skin. Moisturisers should be used to keep the skin supple but not soggy.
  • Bath emollients and shower gels to soothe irritated skin e.g Oilatum ®, E45 ® , Aveeno ®
  • Creams to treat cold sores e.g anti viral acyclovir (Zovirax ®), Compeed patches ®
  • Antiseptic creams e.g Savlon ®, Germolene ®, Dettol ® for minor wounds.
  • Antibacterial creams e.g fucidic acid (Fucidin ®), muciprocin (Bactroban) can be applied sparingly after feeds without need to wash off
  • Preparations to treat corns, warts and veruccas e.g Bazuka ® , Scholl products, Wartner ®
  • Creams to treat athletes food e.g terbinafine (Lamisil ® ), clotrimazole (Canesten ® ), Mycota ® , Mycil ®, Daktarin ®, Scholl products
  • Anti inflammatory gels and creams eg ibuprofen (Ibugel ® ), Diclofenac (Voltarol ® ), Deep Heat ® , Tiger Balm® , taking care not to use these where baby can rub into eyes
  • Medicated shampoos and lotions eg BetaCap ® , Selsun ®, Polytar ®
  • Head lice treatment https://breastfeeding-and-medication.co.uk/fact-sheet/head-lice-and-breastfeeding

Hayfever and breastfeeeding live video and powerpoint training

This is the beginning of the hayfever season with the sun coming out so today I recorded the video about the compatibility of drugs to treat symptoms and breastfeeding

I’ve also uploaded the powerpoint which I used to present this that you can share


Hayfever and breastfeeding powerpoint

Preferred treatment

  • Non sedating antihistamine e.g cetirizine, loratadine, fexofenadine
  • Nasal sprays which act locally e.g. Beconase®, Flixonase®, Mometasone, Nasocort®, Dymista®
  • Eye Drops which act locally e.g sodium cromoglycate

Drugs which may cause drowsiness in mother and nursling may reduce supply e.g acrivastine (Benadryl ® , chlorpheniramine (Piriton ®), promethazine (Phenergan ®)


Technetium 99 studies and Breastfeeding

Earlier this year I had the pleasure of working with Rachel Bidder and others at Swansea Bay University Health Board on compiling information on Having a Tc‑99m Diagnostic Study whilst breastfeeding. Subsequently the information was shared in a presentation to the BNMS conference. In addition, the local team amended their information on MRI and CT to be more breastfeeding friendly.

The information from the Swansea team is reproduced here with their permission. If you have questions regarding expressing and storing, please contact your local breastfeeding team. My thanks to Rachel for allowing me to share this


The vast majority of the radioactivity will be excreted via urine; however, a small amount will be excreted in breast milk. There are some precautions to follow to minimise the radiation dose babies receive. Radioactivity decays over time, meaning that not only will your body excrete it but the radioactivity itself will reduce. For Tc-99m, the radioactivity reduces by half every 6 hours, called the half-life. By following the advice in this leaflet (based on the ARSAC Notes for Guidance, 2022 and Drugs and Lactation Database, 2006), the radiation dose to your child from breastfeeding should be less than half of the annual natural background dose.
The disruption to your breastfeeding depends on the type of diagnostic study you are having. The interruption times given in this leaflet do not apply during the period of early lactation when colostrum is being secreted.

Before Your Appointment
All patients should ‘bank’ at least one feed before their appointment. Do this by expressing milk and storing it appropriately. Check the required breastfeeding interruption time for your scan using the table . It is recommended that you bank enough milk to feed your child over the length of this interruption period. If this is not possible for you then consider an alternative method for feeding your baby over this interruption period, such as using formula. Just before your appointment, you should feed your baby naturally.
After Your Appointment
You should not resume breastfeeding until after the total required period of interruption, as given for your study type in the table on the back of this leaflet. During this period of interruption, you should regularly express milk as fully as possible. This milk should not be used at this point. You can feed your baby during this time using a previously ‘banked’ feed. All milk expressed during the interruption time should either be discarded or stored in the freezer for at least 60 hours after your appointment. After 60 hours (10 half-lives), the radiation will have decayed to a safe level, and the stored milk can be used to feed (there is a small risk with this) or to bathe your baby as you please.
Once the interruption period has passed, you can continue to breastfeed your baby as normal.
Breastfeeding can be undertaken following subsequent pregnancies. Even if you have difficulty
expressing milk, the radioactivity will decay over time and will not be ‘stuck’ in your milk.


Notes for guidance on the clinical administration of radiopharmaceuticals and use of sealed
radioactive sources. Administration of Radioactive Substances Advisory Committee. Feb 2023


“The patient should interrupt breastfeeding for a period of time to ensure that the effective dose received by the infant is less than 1mSv”
To tell a mother with a neonate not to breastfeed for a period of time risks her developing mastitis and will undoubtedly have an impact on her ability in the future to breastfeed
Healthcare professionals have a duty to protect the breastfeeding relationship to support the health of the patient and the breastfeeding infant

See also:

Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501922/

Hale TW Medications and Mothers Milk Online access

Bowel cleansing before colonoscopy and breastfeeding

Just recently I have been contacted by several mothers who were told that they cant breastfeeding during the 24 hour period of bowel prep prior to a colonoscopy or for 24 hours following the procedure under sedation. This is not supported by research and understanding of the pharmacokinetics of the drugs used. It is also a potential risk in that the mother may develop blocked ducts or mastitis necessitating antibiotics if she is unable to express her milk, or in many cases hasn’t been advised to! Not all babies will drink from a bottle so may become dehydrated. Some babies are allergic to cow’s milk protein and may be compromised by 3 days of artificial formula. Hence this fact sheet on the bowel preparations generally used.

It is acceptable to breastfeed as normal during bowel prep. The mother should drink freely of the allowed clear fluids. Someone may be needed to look after the baby during rapid need to evacuate bowels – unless you have taken these products you cant begin to understand the urgency!

PDF of information available


An increasing number of breastfeeding mothers are having colonoscopies to investigate gut problems. The first stage of a colonoscopy is the use of a strong laxative and 24 hours of a fluid only diet to clear out the gut so that the professionals can see the gut in its entirety completely.

Many mothers worry that not eating for 24 hours will reduce their milk supply. Fasting does drop the supply a small amount for some women but frequent feeds seem to overcome problems. It is important to keep drinking the clear fluids which are allowed in order not to dehydrate.

From experience you may find that you need someone else in the house to take the baby urgently when you have to rush to the toilet – there is no waiting! You may find otherwise that you end up feeding whilst on the loo for practical reasons. The bowel washouts produce considerable urgency


One of the most commonly used laxative agents to clear the gut is Movicol ® otherwise known as polyethylene glycol- electrolyte solution. It is a saline laxative which is not absorbed from the gut but pulls water into the bowel to wash the contents out. Because it is not absorbed from the gut it cannot get into breastmilk and would not affect the baby.


This dual sachet product contains macrogol and electrolytes in 2 different sachets, Because it is not absorbed from the gut it cannot get into breastmilk and would not affect the baby.


Sodium picosulfate is not absorbed from the gastrointestinal tract, and its active metabolite, which is absorbed, is not detectable in breastmilk. Breastfeeding can continue as normal.

KleanPrep ®

KleanPrep contains  macrogol 3350 , an osmotic laxative with a high molecular weigh and zero oral bioavailabilty. Like Moviprep it  accumulates water into the GI tract, where it acts as a laxative. It would be very unlikely to enter the plasma of the mother, or milk.


The ingredients magnesium carbonate and citric acid will form an osmotic laxative by pulling water into the bowel and stimulating the bowel to evacuate. Poor oral absorption of magnesium make it unlikely that any will be absorbed from milk to affect the breastfed baby.


Senna is a stimulant laxative. Its key ingredient (anthraquinone), is believed to increase bowel activity due to secretion into the colon. It may produce abdominal cramps. In one study of 23 women who received Senokot none was detectable in their milk.[1] Of 15 mothers reporting loose stools, two infants had loose stools (Werthmann 1973). However, in a randomized, double-blind trial comparing Senokot tablets to placebo, of the women in the study, 126 breastfed their infants and took senna while 155 control mothers breastfed their infants. There was no difference in the percentages of infants in the active and control groups with loose stools or diarrhoea (Shelton 1980). In this study 8 doses were taken. In bowel preparation a single dose only is used.

Werthmann MW Jr, Krees SV. Quantitative excretion of Senokot in human breast milk. Med Ann Dist Columbia. 1973;42:4-5.

Shelton MG. Standardized senna in the management of constipation in the puerperium. A clinical trial. S Afr Med J. 1980;57:78-80.

Phosphate enema (Fleet®)

Sodium phosphate is a saline laxative which sucks water into the lumen of the bowel. Whilst some phosphate may get into the plasma, it is very unlikely to change the levels in milk. The oral bioavailabilty is zero to 20%. Use of phosphate enemas should not require interruption of breastfeeding (LactMed)

Bisacodyl (Dulcolax ®)

Bisacodyl is poorly absorbed from the gut (oral bioavailabilty <5%)  and so reaches low levels in breastmilk. It is a stimulant laxative. Breastfeeding can continue as normal

For information on sedatives  (midazolam, fentanyl, pethidine) used in colonoscopies see separate fact sheet . These also do not preclude normal breastfeeding as soon as the mother is awake and alert.

Ectopic Pregnancy and Breastfeeding

Sadly our family has experienced the tragedy of an ectopic pregnancy and the loss of a very brief dream. This has made me much more aware of the incidence and risk of this condition over. So some more facts – as my friend commented today I hate to waste any opportunity to educate!

I have also heard from several mothers who have been diagnosed with an ectopic pregnancy. They have variously been told that they cant breastfeed again for 2 months and 3 months. One distraught mother planned to pump and dump her milk for 3 months with the hope that she could return to breastfeeding later.

Ectopic pregnancy is a common, occasionally life-threatening condition, that affects 1 in 80 pregnancies. An ectopic pregnancy is when a fertilised egg implants itself outside of the womb, usually in one of the fallopian tubes. Symptoms usually develop between the 4th and 12th weeks of pregnancy. Women with an ectopic pregnancy may still be breastfeeding and wish to continue which can be supported.


  • Ongoing bleeding that is sometimes red or brown/black and watery (like “prune juice”) should be investigated. The bleeding may be heavier or lighter than usual, but pregnancy test is still positive
  • One-sided pain in your tummy which may be persistent or intermittent or a generalised discomfort with bloating and a feeling of fullness (not associated with eating) when lying down.
  • Shoulder tip pain which is often described as pain unlike any you have ever experienced before. (Ectopic Pregnancy Trust)


Your GP will refer you urgently to the early pregnancy unit at your local hospital. You may have your Human Chorionic Gonadotropin (HCG levels) measured over a period of several days. If you are having a normal pregnancy these should double approximately every 48 hours. A smaller increase can indicate a risk of  of this being an ectopic pregnancy but this will be confirmed with ultrasound scans, initially across your tummy. It is likely that a transvaginal (internal) ultrasound scan will be required where a specialised probe is placed into the vagina to get a more detailed look at the reproductive organs.

Unfortunately, if it is confirmed over a period that you have an ectopic pregnancy it is not possible to save the pregnancy and it must be removed either by surgery or the use of methotrexate. The cells have not been able to be nourished and can never develop into the baby you thought you were expecting which can be hard to deal with.

Rupture of ectopic pregnancy

In a few cases, an ectopic pregnancy can grow large enough to split open the fallopian tube. This is known as a rupture which can be very serious, and surgery needs to be carried out as soon as possible.

Signs of a rupture include a combination of:

  • a sharp, sudden and intense pain in your tummy
  • feeling very dizzy or fainting
  • feeling sick
  • looking very pale (NHS Choices)

Methotrexate and breastfeeding

Mothers who are currently breastfeeding an older child can continue 24 hours after the methotrexate is administered.

“It is apparent that the concentration of methotrexate in human milk is minimal, although due to the toxicity of this agent and the unknown effects on rapidly developing neonatal gastrointestinal cells, it is probably wise to pump and discard the mother’s milk for a minimum of 24 hours post dose if given as a single dose (e.g. 50 mg/m2 IM for ectopic pregnancy).

The period in which the mother discards her milk may require extending (consider 4 days of interruption) if the dose used is quite high (>75mg). (Hale 2023). This is due to lack of data from research on accumulation in infant tissues rather than levels in breastmilk.

In a case report of a woman receiving 92 mg IM daily for 3 days (Baker T, Datta P, Rewers-Felkins K, Hale TW. High-dose methotrexate treatment in a breastfeeding mother with placenta accreta: a case report. Breastfeed Med. 2018 Jul/Aug;13(6):450-452 ), milk levels were collected and assayed for methotrexate although she was advised not to breastfeed.dose. Both methotrexate and its metabolite 7-hydroxymethotrexate levels in milk were exceedingly low. On day 2 of therapy, the average milk concentration of methotrexate was 8.6 ng/mL. The maximum concentration of methotrexate occurred at 2 hours and was found to be 16.9 ng/mL. The levels gradually receded and were 4.9 ng/mL at 24 hours. The relative infant dose of methotrexate (RID) was calculated at 0.11%. The half life of methotrexate is quoted as 8-15 hours (Hale 2023).

Infant Monitoring: Should patient resume breastfeeding more than 24 hours after the last dose of maternal therapy, monitor the infant for vomiting, diarrhoea, blood in the vomit, stool or urine. Lab work could be drawn if clinical signs of liver or renal dysfunction, anaemia, thrombocytopenia or an inability to fight infection.

Lactmed reports a study of one mother who was given a single intramuscular dose of 65 mg (50 mg/square meter) of methotrexate for ectopic pregnancy. Six milk samples were obtained from 1 to 24 hours after the dose. Methotrexate was undetectable (<22.7 mcg/L) in all milk samples (Tanaka 2009). In some 20% of cases more than one cycle of methotrexate is required to expel the products of conception. For each cycle breastfeeding should be avoided for 24 hours.

Hale quotes a milk plasma ratio of > 0.08 and relative infant dose of 0.13% – 0.95%. Peak serum concentrations appear 30-60 minutes after intra muscular dose (Jones 2018). Pharmacokinetic data is very variable as there in considerable inter individual variation (Martindale 2017).

Methotrexate and breastfeeding

There is not much information about methotrexate and breastfeeding, but it shows that methotrexate passes into breast milk in tiny amounts. Your doctor or specialist will advise what’s best for you and your baby.

If your weekly dose of methotrexate is 25mg or less, it may be possible to breastfeed. However, you must not breastfeed for 24 hours after taking your medicine. Your midwife or health visitor can give you advice about how to feed your baby while you wait 24 hours. https://www.nhs.uk/medicines/methotrexate/pregnancy-breastfeeding-and-fertility-while-taking-methotrexate/

For more information on methotrexate administration, side effects and monitoring see www.ectopic.org.uk/patients/treatment/

Ectopic pregnancy and breastfeeding fact sheet

Breastfeeding after surgery

After surgery breastfeeding can continue as normal as soon as you are awake and alert. If your nursling is unable to stay in hospital with you, you may need to express to avoid engorgement/blocked duct and to maintain your supply. Your expressed milk can be given to your baby at home. There is no need to pump and dump.

Smoking cessation and breastfeeding

A while ago, in my previous working life I was a smoking cessation counsellor. I’m sure that there are many who tried to quit as a New Year’s Resolution or are considering a pregnancy and want to quit now or who now find themselves pregnant . I reworked a presentation I gave in Blackpool a few years ago so that it is aimed at women but could also help those helping mothers to quit smoking. Let me know if I can help wendy@breastfeeding-and-medication.co.uk

See also the impact of paternal smoking on breastfeeding https://insightplus.mja.com.au/2023/40/the-impact-of-paternal-smoking-on-breastfeeding


Accidentally taking one dose of aspirin when breastfeeding

It is surprising how often mums manage to take products containing aspirin by mistake – they are given by well meaning partners, friends at the office or just taken quickly for pain. Then the realisation that aspirin is contra indicated in breastfeeding. What to do? How long to express?

The answer is actually simple with one single accidental exposure. The risk is low and I have been unable to find any references associating Reye’s syndrome with the amount of aspirin passing through breastmilk.

Reye’s syndrome This is a rare syndrome, characterised by acute encephalopathy and fatty degeneration of the liver, usually after a viral illness or chickenpox. The incidence is falling but sporadic cases are still reported. It was often associated with the use of aspirin during the prodromal illness. Few cases occur in white children under 1 year although it is more common in black infants in this age group. Many children retrospectively examined show an underlying inborn error of metabolism.

accidental/one off dose of aspirin factsheet

Aspirin is not generally recommended to be used by lactating women due to the link between aspirin and Reye’s syndrome. Aspirin is 80–90% bound to plasma proteins. Erickson and Oppenheim (1979) found that even at a dose of 4 g per day the levels of salicylate measured in one mother suffering from rheumatoid arthritis were below the level of detection. Findlay et al. (1981) studied two mothers exposed to 454 mg aspirin. They found that salicylic acid penetrated poorly into milk, with peak levels of only 1.12–1.60 µg per millilitre, and estimated that about 0.1% of the mothers’ total dose would appear in breastmilk.

Accidental consumption of a single dose of aspirin by a lactating mother need not lead to expressing and discarding of her breastmilk. Theoretical infant dose through breastmilk is quoted as 0.25 mg per kilogramme per day with a relative infant dose quoted as 2.5–10.8% (Hale 2017 online access).

The BNF states: ‘Avoid – possible risk of Reye’s syndrome; regular use of high doses could impair platelet function and produce hypoprothrombinaemia in infant if neonatal vitamin K stores low’. Vitamin K is secreted in breastmilk and is added to formula.

If taken accidentally no evidence that continuing to breastfeed after single dose is harmful.


Erickson SH, Oppenheim GL, Aspirin in breastmilk, J Fam Pract, 1979;8(1):189–90.

Findlay JW, DeAngelis RL, Kearney MF, Welch RM, Findlay J, Analgesic drugs in breastmilk and plasma, Clin Pharmacol Ther, 1981;29:625–33.

Glasgow JF, Reye’s syndrome: the case for a causal link with aspirin, Drug Saf, 2006;29(12): 1111–21.

Leave a comment

Logged in as Wendy JonesLog out?


Follow us