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Tirzepatide (Mounjaro™) and Breastfeeding
Tirzepatide is a long-acting GIP (glucose-dependent insulinotropic polypeptide) receptor and GLP-1 (glucagon-like peptide-1) receptor agonist that increases insulin sensitivity and secretion, suppresses glucagon secretion, and slows gastric emptying.
Tirzepatide is used to treat Type 2 diabetes mellitus as monotherapy (if metformin is inappropriate), or in combination with other antidiabetic drugs (including insulin) if existing treatment fails to achieve adequate glycaemic control. It is also used in the treatment of obesity by weekly subcutaneous administration.
No information is available on the clinical use of tirzepatide during breastfeeding. Because tirzepatide is a large peptide molecule with a molecular weight of 4814 Da, the amount in milk is likely to be low and absorption is unlikely because it is probably partially destroyed in the infant’s gastrointestinal tract. Until more data become available, tirzepatide should be used with caution during breastfeeding, especially while nursing a newborn or preterm infant. (LactMed).
Due to its protein nature, it is inactivated in the gastrointestinal tract and is not absorbed (oral bioavailability is practically nil), which makes it difficult or impossible for it to pass into the infant’s plasma from ingested breast milk, except in premature infants and in the immediate neonatal period, where there may be greater intestinal permeability. (E-lactancia).
While caution is still necessary without confirmatory data, it is unlikely to be present in large quantities in the milk compartment (Hale )
See also https://www.infantrisk.com/content/weight-loss-lactation
https://www.springerpub.com/blog/weight-loss-drugs-breastfeeding
Hale and Krutsch (Infantrisk pharmacists express concern on the use of weight loss medications and breastfeeding due to inadequate consumption of nutrients.
“Concerns have been expressed about how the pharmacodynamics of GLP-1 agonists such as tirzepatide or semaglutide could impact the nutritional constituents of milk. These drugs are analogs of natural GLP-1 with small modifications to slow their degradation by the DPP-4 enzyme. However, lactation, in general, is expected to occur during a catabolic physiological state – GLP-1 agonists catalyze the catabolism to encourage weight loss. As long as the mother has sufficient weight to lose, the nutrient profile of milk would likely be similar if compared to a diet producing equivalent weight loss. If a mother is reducing caloric intake for any reason, we recommend a postnatal vitamin and attention to consuming enough calories to meet the elevated nutrient needs required during lactation”.
June 2025 the MHRA recommended that all women taking “skinny jabs” should use effective contraception.
“Effective contraception includes oral (the pill) and non-oral (the implant, coil or condoms) forms of contraception. However, Mounjaro may reduce the effectiveness of oral contraceptives in those who are overweight. Therefore, those taking Mounjaro who are overweight and are using an oral form of contraception are advised to also use a non-oral form of contraception. This only applies to those taking Mounjaro and is especially important for the four weeks after starting Mounjaro and after any dose increase”
Other sources of information
NICE TA 1026 Tirzepatide for managing overweight and obesity . https://www.nice.org.uk/guidance/ta1026
See also Semaglutide and Breastfeeding https://breastfeeding-and-medication.co.uk/fact-sheet/semaglutide-and-breastfeeding
Liraglutide and Breastfeeding https://breastfeeding-and-medication.co.uk/fact-sheet/liraglutide-saxenda-and-breastfeeding
Liraglutide (Saxenda) and Breastfeeding


June 2025 the MHRA recommended that all women taking “skinny jabs” should use effective contraception.
“Effective contraception includes oral (the pill) and non-oral (the implant, coil or condoms) forms of contraception. However, Mounjaro may reduce the effectiveness of oral contraceptives in those who are overweight. Therefore, those taking Mounjaro who are overweight and are using an oral form of contraception are advised to also use a non-oral form of contraception. This only applies to those taking Mounjaro and is especially important for the four weeks after starting Mounjaro and after any dose increase”
This document can be downloaded as a pdf here
https://breastfeeding-and-medication.co.uk/wp-content/uploads/2023/01/liraglutide-and-bf-.pdf
see also https://www.springerpub.com/blog/weight-loss-drugs-breastfeeding/
Liraglutide binds to, and activates, the GLP-1 (glucagon-like peptide-1) receptor to increase insulin secretion, suppress glucagon secretion, and slow gastric emptying.
Saxenda™ is given as an adjunct in weight management [in conjunction with dietary measures and increased physical activity in individuals with a body mass index (BMI) of 30 kg/m2 or more, or in individuals with a BMI of 27 kg/m2 or more in the presence of at least one weight-related co-morbidity] by self-administered subcutaneous injection (BNF).
Victoza™ is given for Type 2 diabetes mellitus as monotherapy (if metformin inappropriate or not tolerated), or in combination with other antidiabetic drugs, (including insulin) if existing treatment fails to achieve adequate glycaemic control (BNF).
Compatibility with breastfeeding
- It is currently not known if liraglutide is excreted in human milk. The molecular weight of this medication means that it would have great difficulty entering breast milk. It is described as having zero oral bioavailability which is why it is given subcutaneously as a drug. In consequence very little of this medication would be absorbed by the infant orally even if found in breast milk. The risk of this in a breastfed infant would be expected to be very low (Hale and Krutsch).
- The manufacturer advises it is avoided in lactation due to lack of studies so its use in a lactating mother would be outside of the product licence. However, animal studies suggest that transfer into milk is low, but excretion into human milk not known (a tertiary source confirms lack of information in human lactation, but also states that risk to infants appears to be negligible. Blood glucose monitoring of the infant should be considered) (BNF)
- No information is available on the excretion of liraglutide int milk or its clinical use during breastfeeding. Because liraglutide is a large peptide molecule with a molecular weight of 3751 daltons, the amount in milk is likely to be very low and absorption is unlikely because it is probably destroyed in the infant’s gastrointestinal tract. Until more data become available, liraglutide should be used with caution during breastfeeding, especially while nursing a new-born or preterm infant. (https://www.ncbi.nlm.nih.gov/books/NBK500977/)
- Elactancia cites liraglutide as of very low risk in lactation ( https://www.e-lactancia.org/breastfeeding/liraglutide/product/). Due to its protein nature, it deteriorates in the gastrointestinal tract, not being absorbed. Its pharmacokinetic data (high molecular weight and high percentage of plasma protein binding) make it very unlikely that significant amounts will pass into breast milk except in preterm infants and in the immediate neonatal period when there may be increased permeability.
Common or very common side effects
Appetite decreased; asthenia; burping; constipation; diarrhoea; dizziness; dry mouth; gallbladder disorders; gastrointestinal discomfort; gastrointestinal disorders; headache; increased risk of infection; insomnia; nausea; skin reactions; taste altered; toothache; vomiting (BNF).
Monitoring of nursling for side effects
Although adverse effects have not been noted the baby should be monitored for Vomiting, diarrhoea and signs of hypoglycaemia- drowsiness, lethargy, pallor, sweating, tremor (Hale and Krutsch)
Can my GP prescribe Saxenda™ in the UK for weight loss?
Saxenda™ is approved for use within the NHS in the UK. However, your GP or family doctor is unlikely to be able to prescribe it to you and it is usually only available but only through a specialist weight management service or privately.
References
Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501922/
Hale TW and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (online access HalesMeds.com January 2023)
Joint Formulary Committee (2022) British National Formulary. [Online]. London: British Medical Association and Royal Pharmaceutical Society of Great Britain. Available at: Medicines Complete Database, [Accessed January 2023].
Elactancia Is it compatible with breastfeeding? https://www.e-lactancia.org/
Semaglutide and Breastfeeding
Following the recommendation by NICE (March 2023) I looked at the evidence on semaglutide and breastfeeding. There are no current published reports, only theory from pharmacokietics.
I have found the ZOE podcast interesting (no financial involvement) https://link.chtbl.com/s9cwxMzY
And Margaret MCartnetny view in the BMJ https://www.bmj.com/content/380/bmj.p624.full
see also https://www.springerpub.com/blog/weight-loss-drugs-breastfeeding/
June 2025 the MHRA recommended that all women taking “skinny jabs” should use effective contraception.
“Effective contraception includes oral (the pill) and non-oral (the implant, coil or condoms) forms of contraception. However, Mounjaro may reduce the effectiveness of oral contraceptives in those who are overweight. Therefore, those taking Mounjaro who are overweight and are using an oral form of contraception are advised to also use a non-oral form of contraception. This only applies to those taking Mounjaro and is especially important for the four weeks after starting Mounjaro and after any dose increase”
Pdf of factsheet :
https://breastfeeding-and-medication.co.uk/wp-content/uploads/2023/03/semaglutide-and-breastfeeding-.pdf

Semaglutide binds to, and activates, the GLP-1 (glucagon-like peptide-1) receptor to increase insulin secretion, suppress glucagon secretion, and slow gastric emptying.
Semaglutide is used to treat Type 2 diabetes mellitus as monotherapy (if metformin inappropriate), or in combination with other antidiabetic drugs (including insulin) if existing treatment fails to achieve adequate glycaemic control. In March 2023 it was recommended for the treatment of obesity in specific circumstances.
Use in obesity.
Semaglutide (Wegovy™) was recommended by the National Institute for Health and Care Excellence (NICE) to treat thousands of people with obesity in England (March 2023). Semaglutide will be allowed to be prescribed to help people lose weight as part of their treatment in an NHS specialist weight management service. The drug works by suppressing appetite by mimicking the hormone glucagon-like peptide-1 (GLP-1), which is released after eating. It is injected once a week by patients. NICE first recommended the drug in draft guidance 2022, after a clinical trial of just under 2000 volunteers found that people lost on average 12% more weight with semaglutide alongside supervised weight loss coaching (BMJ 2023;380:556).
Guidelines for use in obesity
Semaglutide is recommended as an option for weight management, including weight loss and weight maintenance, alongside a reduced-calorie diet and increased physical activity in adults, only if:
- it is used for a maximum of 2 years, and within a specialist weight management service providing multidisciplinary management of overweight or obesity (including but not limited to tiers 3 and 4), and
- they have at least 1 weight-related comorbidity and:
- a body mass index (BMI) of at least 35.0 kg/m2, or a BMI of 30.0 kg/m2 to 34.9 kg/m2 and meet the criteria for referral to specialist weight management services in NICE’s guideline on obesity: identification, assessment and management.
Consideration should be made to stop semaglutide if less than 5% of the initial weight has been lost after 6 months of treatment. (https://www.nice.org.uk/guidance/TA875/chapter/1-Recommendations)
Currently Wegovy is not commercially available. Ozempic is available but is not licensed for weight management but only treatment of diabetes.
Dose
By subcutaneous injection( Ozempic™ ): Initially 0.25 mg once weekly for 4 weeks, then increased to 0.5 mg once weekly for at least 4 weeks, then increased if necessary to 1 mg once weekly.
By mouth (Rybelsus™): Initially 3 mg once daily for 1 month, then increased to 7 mg once daily for at least 1 month, then increased if necessary to 14 mg once daily, dose to be taken on an empty stomach, one 14 mg tablet should be used to achieve a 14 mg dose; use of two 7 mg tablets to achieve a 14 mg dose has not been studied and is therefore not recommended; maximum 14 mg per day.
By subcutaneous injection (Wegovy™): initially 0.25 mg once a week and increased every 4 weeks until the full dose of 2.4 mg is reached.
Compatibility with breastfeeding
- It is currently not known if semaglutide is excreted in human milk. The molecular weight of this medication means that it would have great difficulty entering breast milk. It is described as having oral bioavailability < 1% although an oral preparation exists. In consequence very little of this medication would be absorbed by the infant orally even if found in breast milk. The risk of this in a breastfed infant would be expected to be very low (Hale and Krutsch).
- Manufacturer advises avoid stating that it is present in milk in animal studies. so its use in a lactating mother would be outside of the product licence (BNF)
- No information is available on the clinical use of semaglutide during breastfeeding. Because semaglutide is a peptide molecule with a molecular weight of 4113 daltons and is over 99% protein bound, the amount in milk is likely to be very low. Absorption by the infant is unlikely because the drug is probably destroyed in the infant’s gastrointestinal tract. Until more data become available, semaglutide should be used with caution during breastfeeding, especially while nursing a new-born or preterm infant. (https://www.ncbi.nlm.nih.gov/books/NBK500980/)
- Elactancia cites semaglutide as of very low risk in lactation (https://www.e-lactancia.org/breastfeeding/semaglutide/product/ ). Its high molecular weight and high fixation to plasma proteins make it very unlikely to pass into mothers’ milk in a clinically significant quantity. (Serrano 2015). In addition, due to its protein nature it is inactivated in the gastrointestinal tract, not being absorbed (practically null oral bioavailability), which hinders or prevents the passage into plasma of the infant from ingested breast milk (Serrano 2015), except in premature infants and during the immediate neonatal period, in which there may be greater intestinal permeability.
Common or very common side effects
Appetite decreased; burping; cholelithiasis; constipation; diarrhoea; dizziness; fatigue; gastrointestinal discomfort; gastrointestinal disorders; hypoglycaemia (in combination with insulin or sulfonylurea); nausea; vomiting; weight decreased (BNF).
There are recent reports of eye problems following use of semaglutide, https://www.aao.org/newsroom/news-releases/detail/weight-loss-drug-and-eye-health
Monitoring of nursling for side effects
Although adverse effects have not been noted the baby should be monitored for decreased appetite, abdominal distension, GERD, constipation, diarrhoea. (Hale and Krutsch)
Can my GP prescribe Wegovy™ in the UK for weight loss?
Semaglutide can only be prescribed as part of a specialist (tertiary) weight management service with multidisciplinary input and for a maximum of two years. https://www.nice.org.uk/guidance/ta875/chapter/1-Recommendations
Conception and contraception
Manufacturer advises women of childbearing potential should use effective contraception during and for at least two months after stopping treatment.
References
Drugs and Lactation Database (LactMed) https://www.ncbi.nlm.nih.gov/books/NBK501922/
Hale TW and Krutsch K Hale’s Medications & Mothers’ Milk™ 2023: A Manual of Lactational Pharmacology (online access HalesMeds.com January 2023)
Joint Formulary Committee (2022) British National Formulary. [Online]. London: British Medical Association and Royal Pharmaceutical Society of Great Britain. Available at: Medicines Complete Database, [Accessed January 2023].
Elactancia Is it compatible with breastfeeding? https://www.e-lactancia.org/
Serrano Aguayo P, García de Quirós Muñoz JM, Bretón Lesmes I, Cózar León MV. Tratamiento de enfermedades endocrinológicas durante la lactancia. [Endocrinologic diseases management during breastfeeding.] Med Clin (Barc). 2015 Jan 20;144(2):73-9.

ADHD and Breastfeeding
I have shared the chapter on ADHD from my book Breastfeeding and Chronic Medical Conditions multiple times this week. Many mothers seem to be diagnosed in later life and are concerned about breastfeeding. Hope this is a useful link.
More information
ADHD and Breastfeeding Factsheet
https://infantrisk.com/content/adhd-medications-and-breastfeeding
I came off my medication to conceive and my baby is now 6 months old. I am really struggling to think straight now and getting really overwhelmed by the smallest of things.
Description
ADHD is a disorder that includes symptoms such as inattentiveness, hyperactivity, and impulsiveness. It is normally diagnosed in childhood, but some parents have found themselves being diagnosed when seeking a diagnosis for their children. The cause is unknown, but it seems to at least in part, genetic. It has been suggested that being born prematurely (before the 37th week of pregnancy), having a low birth weight or maternal smoking or alcohol or drug abuse during pregnancy may be linked. Attention deficit hyperactivity disorder (ADHD) is thought to affect about 1 in 20 children in the UK with incidence being three times higher in boys.
Symptoms fall into 2 categories:
inattentiveness main symptoms of which are:
- having a short attention span and being easily distracted
- making careless mistakes
- appearing forgetful or losing things
- being unable to stick to tasks that are tedious
- appearing to be unable to listen to or carry out instructions
- constantly changing activity or task
- having difficulty organising tasks
hyperactivity and impulsiveness main symptoms of which are:
- being unable to sit still and constantly fidgeting
- being unable to concentrate on tasks
- excessive physical movement
- excessive talking
- being unable to wait turn
- acting without thinking
- interrupting conversations
- little or no sense of danger
- ADHD may be linked with anxiety, autism, and several other conditions. By the age of 25, an estimated 15% of people diagnosed with ADHD as children still have a full range of symptoms, and 65% still have some symptoms that affect their daily lives. ( https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/symptoms/)
Treatment
- Methylphenidate (Ritalin ™, Concerta ™); works by increasing the amount of a dopamine in the parts of the brain responsible for self-control and attention. It is usually the first line treatment. There are side effects of loss of appetite and difficulty sleeping and mood swings. Limited evidence indicates that methylphenidate levels in milk are very low and not detectable in infant serum. The effects of methylphenidate in milk on the neurological development of the infant have not been well studied. Monitor the baby for agitation, irritability, poor sleeping patterns, changes in feeding and poor weight gain.
- Atomexatine is a selective noradrenaline reuptake inhibitor (SNRI), increasing levels of noradrenaline rather than dopamine. It can aid concentration and help control impulses. Side effects include rise in blood pressure and heart rate, nausea and vomiting, gastric pain, difficulty sleeping, dizziness, headaches, and irritability. More importantly it has been associated with suicidal thoughts and liver damage. There is no published experience with atomoxetine during breastfeeding, although reports from the manufacturer found no serious adverse effects in two breastfed infants (Besag 2014).
- Dexamphetamine. Side effects include decreased appetite, mood swings, agitation and aggression, dizziness, headaches, nausea, vomiting and diarrhoea. Only used if lisdexamphetamine is helpful but not tolerated. In dosages prescribed for medical indications, some evidence indicates that dextroamphetamine might not affect nursing infants adversely. The effect of dextroamphetamine in milk on the neurological development of the infant has not been well studied. It is possible that large dosages of dextroamphetamine might interfere with milk production. Infant Monitoring for agitation, hyperactivity, insomnia, decreased appetite, weight gain, and tremor.
- Lisdexamphetamine (Vyvance ™) may be offered as first line treatment in adults. Side effects include decreased appetite, aggression or drowsiness, dizziness, headaches, nausea, vomiting and diarrhoea. Lisdexamfetamine is a prodrug of dextroamphetamine. In medicinal dosages, some evidence (5 mothers studied) indicates that dextroamphetamine might not affect nursing infants adversely. The effect of dextroamphetamine in milk on the neurological development of the infant has not been well studied. Infant Monitoring should be for agitation, irritability, poor sleeping patterns and poor weight gain.
- The NHS website suggests that for adults with ADHD if you find it hard to stay organised, then make lists, keep diaries, stick up reminders and set aside some time to plan what you need to do
- let off steam by exercising regularly
- find ways to help you relax, such as listening to music or learning relaxation techniques
- if you have a job, speak to your employer about your condition, and discuss anything they can do to help you work better
- talk to your doctor about your suitability to drive, as you will need to tell the Driver and Vehicle Licensing Agency (DVLA) if your ADHD affects your driving
- contact or join a local or national support group – these organisations can put you in touch with other people in a similar situation, and can be a good source of support, information, and advice
References
- Attention deficit hyperactivity disorder: diagnosis and management; NICE guideline (March 2018, updated September 2019)
- Attention deficit hyperactivity disorder; NICE CKS, May 2018
- Besag FM. ADHD treatment and pregnancy. Drug Saf. 2014; 37:397-40
- NHS ADHD https://www.nhs.uk/conditions/attention-deficit-hyperactivity-disorder-adhd/living-with/
- Further Information
- AADUK https://aadduk.org/
Can women with ADHD stay on medication while they breastfeed?
Anecdotally there are many mothers who take medication for ADHD during their breastfeeding journey despite a lack of published studies on the effect of the level of medication passing through breastmilk to babies. It is a topic regularly raised on social media discussions from which many parents take their information. Since the pandemic the increase in diagnoses of adults has driven the discussions too.
As with many drugs we rely on the pharmacokinetics of the products: that is the way that the drugs are handled by the body. Drugs used to treat ADHD are not recommended during breastfeeding as the manufacturers are not required to take responsibility as they cannot ethically conduct clinical trials during the development of the medication. This is true of virtually all products used by breastfeeding women – they are used outside of the product licence and prescribed with the professionals being required to take responsibility.
For example methylphenidate (Concerta™ and Ritalin™) was studied in 3 women taking between 35 and 80mg daily. The average milk levels measured were very low. The infants had no drug-related adverse reactions and were developing normally for their ages which averaged 4.4 months. No adverse events have been identified according to specialist sources although it would be wise to monitor changes in sleep patters and feeding including weight gain.
What ones are safest?
It is difficult to say which one is “safest” as this is a relative term. No drug is absolutely safe, but all of the drugs used to treat ADHD are recognised as compatible with breastfeeding by expert, specialist sources. The drug which would generally be chosen is the one that has proven to be most effective for the mother. Methylphenidate could perhaps be said to have the best evidence but as has already been discussed, the data published is limited. The decision to prescribe should be agreed between the mother and her professionals with full, accessible information so that she can make an informed choice in the risks and benefits for her and her nursling. Ongoing breastfeeding has many health advantages but if the mother has concerns about exposing her child to the medication (in however low a level) that may influence her choice as to whether to take the drug and continue to breastfeed, breastfeed but delay the drug or take the medication and choose to formula feed. We all have individual feelings as to the risks and benefits of each choice.
Is there a risk to the baby at all?
In the first 6 weeks after birth a baby has immature kidney and liver function and is at greater risk of not being able to metabolise the levels of drug passing through breastmilk. This in turn makes it more likely that side effects such as changes in sleep and feeding patters may occur but are difficult to identify from normal neonatal behaviour.
Individual reactions are always possible although reporting in specialist expert sources suggest these are limited.
Is it advised to stay on rather than coping without it?
That is very much an individual decision depending on how well the mother is coping with her symptoms alongside the complexity of life with a newborn which will all be associated with loss of routine and long periods sitting to breastfeed. Most mothers stop medication during pregnancy and may be desperate to re start. A fully informed discussion with appropriate, accessible data puts the decision with the mother on what she feels comfortable with.
Specialist sources of information
https://www.ncbi.nlm.nih.gov/books/NBK501922
https://www.sps.nhs.uk/articles/safety-in-lactation-drugs-for-adhd
Living with ADHD
This has nothing to do with breastfeeding and medication but was forwarded to me by a teacher and her students (Danielle) who were researching for Learning Disability Week. I hope knowing that they are helping others will empower them and also share their experience with families living with ADHD.
Thriving in College with ADHD: Essential Tools and Strategies for Success
https://abamastersprograms.org/thriving-in-college-with-adhd/
and

Fremanezumab (Ajovy™) and Breastfeeding
Fremanezumab is a humanised monoclonal antibody that binds to the calcitonin gene-related peptide (CGRP) ligand, inhibiting the function of CGRP at its receptor, and thereby preventing migraine attacks (BNF). It is given as a sub cutaneous injection of 225 mg once a month, alternatively 675 mg every 3 months.
Fremanezumab is recommended for patients who have 4 or more migraine days a month and for whom at least 3 preventive drug treatments have failed and the drug is supplied by the company under a commercial agreement agreed with NICE. It is unclear if fremanezumab works better than botulinum toxin type A (NICE)
It has a molecular weight of 148,000 and assumed low oral bioavailability. However, there are no studies in breastfeeding mothers and babies although any passing into milk is presumed to be destroyed in the infant gut (LactMed)
References
- Fremanezumab for preventing migraine TA 764 Feb 2022 https://www.nice.org.uk/guidance/ta764
- BNF Fremanezumab | Drugs | BNF | NICE
- LactMed https://www.ncbi.nlm.nih.gov/books/NBK532493/
Threadworm, mebendazole and breastfeeding
It has been suggested that up to 40% of children get threadworms at some stage. The whole family needs to be treated, even the breastfeeding mother. The joys of being a mum!
Factsheet pdf available here:


Symptoms of threadworms
Threadworms are very common in toddlers and primary school age children who can sadly infect the rest of the family. They are not a sign of poor hygiene. The exact prevalence is not known but it has been estimated that up to 40% of children in the UK will have threadworm infestation at some time in their lives. The symptoms are:
- Intense itching around the anus, typically worse during the night.
- Some people may not experience itching but small white thread-like worms (which may be slowly moving) are seen on the perianal skin or in the stools.
- In females, there may be itching around the vulva/vagina.
- Night-time itching may lead to disturbed sleep and irritability.
Treatment
Everyone in the household needs to be treated with mebendazole ( available over the counter as Ovex™ or on prescription as Vermox™. Mebendazole can be given at a dose of 100mg to everyone over the age of 6 months. Mebendazole kills the worms but not the eggs which can survive for up to 2 weeks. If reinfection occurs, second dose may be needed after 2 weeks.
Prevention of re-infection
https://www.nhs.uk/conditions/threadworms/
- wash hands and scrub under fingernails – particularly before eating, after using the toilet or changing nappies
- encourage children to wash hands regularly particularly under nails
- bathe or shower every morning
- rinse toothbrushes before using them
- keep fingernails short
- wash sleepwear, sheets, towels and soft toys (at a hot temperature)
- disinfect kitchen and bathroom surfaces (particularly the area behind the toilet as eggs may spread if the child scratches
- vacuum and dust with a damp cloth
- make sure children wear underwear at night – change it in the morning
- change toys such as Playdough which can get behind fingernails and become infected with eggs if the child has scratched and not washed hands
Eggs can pass to other people when they touch contaminated surfaces and then touch their mouth. They take around 2 weeks to hatch.

Threadworms in pregnancy
https://www.medicinesinpregnancy.org/Medicine–pregnancy/Mebendazole/
Babies under 6 months
Treat with hygiene measures only and watch for signs when changing nappies
Treating Babies 6 months to 2 years
Unlicensed so may need to be prescribed Mebendazole | Drugs | BNF | NICE
Threadworms when breastfeeding
Oral bio availability poor 2-10%, Highly plasma protein bound, Relative Infant Dose 0.06%.
It is unlikely that mebendazole is transmitted to the infant in clinically relevant concentrations and breastfeeding can continue as normal even if the nursling is also receiving a dose.
Other sources of information
A-Z NHS Conditions
Elactancia https://www.e-lactancia.org/breastfeeding/mebendazole/product/
BNF Mebendazole https://bnf.nice.org.uk/drugs/mebendazole/ “Amount present in milk too small to be harmful but manufacturer advises avoid”
McCormick, A., Fleming, D. and Charlton, J. (1995) Morbidity statistics from general practice. Fourth national study 1991-1992. Office of Population Censuses and Surveys. http://www.statistics.gov.uk
CKS Threadworm https://cks.nice.org.uk/topics/threadworm/
The menopause and breastfeeding
I’m seeing increasing numbers of questions form mums in the perimenopause who are still breastfeeding. Maybe they delivered later or maybe they have been feeding to term or maybe lots of other reasons. I remember asking for blood tests to check my hormone levels because I just couldn;t think clearly anymore and my memory was poor which wasn;t ideal as I was just becoming an independent pharmacist prescriber! My levels had indeed dropped and I went on to HRT. This may not be everyone’s choice or be suitable for them
I have spent many hours this year looking for guidance on HRT and breastfeeding and failed to find any studies or conclusive data. Everything is anecdotal at the moment but I hope this information helps.
One vital piece of information – please keep checking your breasts for lumps . HRT can slightly increase the risk of breast cancer. If you’ve had breast cancer you’ll usually be advised not to take HRT. The increased risk is low: there are around 5 extra cases of breast cancer in every 1,000 women who take combined HRT for 5 years. The risk increases the longer you take it, and the older you are.
Risk of breast cancer BNF June 2024 Sex hormones | Treatment summaries | BNF | NICE
All types of systemic (oral or transdermal) HRT treatment increase the risk of breast cancer after 1 year of use. This risk is higher for combined oestrogen-progestogen HRT (particularly for continuous HRT preparations where both oestrogen and progestogen are taken throughout each month) than for oestrogen-only HRT, but is irrespective of the type of oestrogen or progestogen. Longer duration of HRT use (but not the age at which HRT is started) further increases risk.
Although the risk of breast cancer is lower after stopping HRT than it is during current use, the excess risk persists for more than 10 years after stopping compared with women who have never used HRT. Vaginal preparations containing low doses of oestrogen to treat local symptoms are not thought to be associated with an effect on breast cancer risk.
The MHRA advises discussing the updated information on the risk of breast cancer with women who use or are considering starting HRT, at their next routine appointment.
There are also risks of endometrial cancer, ovarian cancer, thromboembolism, stroke and coronary vascular disease. Please do not use higher than recommended/licensed doses of HRT.
As usual please message me on wendy@breastfeeding-and-medication.co.uk if you have a question
The Menopause And Breastfeeding
There remains no conclusive research on the passage of HRT medication into breastmilk. It appears anecdotally that there is less impact on milk supply from using transdermal preparations than oral medication. There remains the possibility of reduction in lactation due to the oestrogen contact inhibiting prolactin. Anecdotally HRT at standard dose has been used by breastfeeding women without impact on the nursling or supply. There is no research on higher doses or use outside of licence application.
For use of vaginal oestrogen see https://breastfeeding-and-medication.co.uk/fact-sheet/breastfeeding-and-oestrogen-cream-or-pessary
I typed “menopause and breastfeeding” into a well-known search engine and what came up first was “It is most likely that you are suffering from menopausal-like symptoms due to breastfeeding. After childbirth and during breastfeeding, women’s oestrogen levels can drop to lower levels than usual. These low levels of oestrogen can cause symptoms that mimic menopause.”
Whilst in a paper published in 2020 Langton et al found that after studying 100,000 women ages 25 to 42 years in the Nurses’ Health Study II (an analysis funded by the National Institutes of Health) “Women who breastfed their infants exclusively for seven to 12 months may have a significantly lower risk of early menopause than their peers who breastfed their infants for less than a month”. The study also suggests that pregnancy can reduce the risk of early menopause.”
As many women now give birth later than in the past, due to changes in work and finance, and feed until they and their nursling choose to stop, questions that I have received from mothers exhibiting signs of early menopause have increased substantially. Most women begin the menopause between 45 and 55 years of age.
There is also a group who have experienced premature ovarian failure which may be hereditary. There is a further group who have had their uterus and ovaries removed surgically for a variety of reasons.
Premature ovarian insufficiency (POI)
This affects about one in a hundred women under 40 in the UK. It occurs when the ovaries no longer produce normal amounts of estrogen and therefore may not produce eggs. This means that periods will become irregular or stop altogether, with symptoms of the menopause. Many women have POI without actually realising it. Any mother under the age of 40 and having irregular periods (or if they have even stopped completely) should be talk to their doctor about having further tests. Unlike the normal menopause when the ovaries stop working completely, in POI ovarian function can be intermittent, occasionally resulting in a period, ovulation or even pregnancy. This intermittent return of ovarian function means that 5–10% of women with POI will conceive spontaneously.
Perimenopause
The period leading up to the menopause, when hormone production decreases symptoms may start to be experienced is defined as the perimenopause. The period is rather ill defined and may vary dramatically between women. It usually suggested as beginning with irregular menstruation. There may be changes to flow with periods becoming heavier or lighter. For others it may be defined by mood swings or changes in mental function. Each person has a different awareness of their own bodies. This is the period in which most calls about breastfeeding appear to originate with a request to begin hormone replacement therapy.
Menopause
The menopause is defined as an absence of menstruation for over a year. Not all symptoms will be experienced by all women, we are all different.
Typical menopausal symptoms, include:
- hot flushes
- night sweats
- vaginal dryness and discomfort during sex
- difficulty sleeping
- low mood or anxiety
- reduced sex drive (libido)
- problems with memory and concentration
Post menopause
This is defined as the remainder of a women’s life which can present with an increased risk of osteoporosis although the risk is lowered in women who have breastfed (https://www.unicef.org.uk/babyfriendly/news-and-research/baby-friendly-research/maternal-health-research/maternal-health-research-bone-density/).
HRT and Breastfeeding
HRT contains oestrogen and sometimes a progesterone e.g., norethisterone, not that dissimilar to that in the combined oral contraceptive which can be used in breastfeeding. The ethinylestradiol content of COCs range from 20–40 micrograms whilst that in HRT products contain 1 – 2 milligrams of estradiol (there are 1000 micrograms in a milligram).
However, Hale says “Although small amounts of Conjugated estrogens may pass into breastmilk, the effects of estrogens on the infant appear minimal. Early postpartum use of estrogens may reduce volume of milk produced and the protein content, but it is variable and depends on dose and the individual.”
“Conjugated estrogens comprise more than 90% of the total estrogen content of human milk and plasma (McGarrigle) Estriol glucosiduronates were the predominant oestrogen metabolites (63%) in plasma”
His conclusion is that low levels pass into milk confirmed in a query to the InfantRisk forum (https://www.infantrisk.com/forum/forum/medications-and-breastfeeding-mothers/medications-and-mothers-milk/339-hormone-replacement-therapy )
Martindale (39th Ed) states that estradiol has been detected in breastmilk after the use of pessaries containing estradiol 50 or 100mg (Nilsson 1978) and that the American Academy of Pediatrics (2001) considers that it is compatible with breastfeeding
Pharmacokinetics of HRT (Taken from Hale)
Conjugated estrogens: Milk plasma ratio 0.08, Plasma Protein Binding 98%
References
- American Academy of Pediatrics Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 Sep;108(3):776-89.
- Chollet, J. A., G. Carter, et al. (2009). “Efficacy and safety of vaginal estriol and progesterone in postmenopausal women with atrophic vaginitis.” Menopause 16(5): 978-983.
- Hale TW Medications and Mothers Milk online access
- Langton CR, Whitcomb BW, Purdue-Smithe AC, et al. Association of Parity and Breastfeeding With Risk of Early Natural Menopause. JAMA Netw Open. 2020;3(1): e1919615)
- Martindale The Complete Drug Reference 39 Ed. Pharmaceutical Press
- McGarrigle HH, Lachelin GC. Oestrone, oestradiol and oestriol glucosiduronates and sulphates in human puerperal plasma and milk. J Steroid Biochem. 1983May;18(5):607-11.
- Nilsson S, Nygren KG, Johansson ED. Transfer of estradiol to human milk. Am J Obstet Gynecol. 1978 Nov 15;132(6):653-7

Citalopram and breastfeeding
Especially since the pandemic many more mothers have been asking about the compatibility of citalopram during breastfeeding. It has been a hard time for everyone with the incidence of anxiety and depression continuing to rise. As access to IAPT ( https://www.england.nhs.uk/mental-health/adults/iapt/) may be more difficult the prescription of medication is inevitable. Alternative CBT access may be available on line via and IESO (https://www.iesohealth.com/en-gb)
Citalopram is widely used and we have a high level of experience with it over many years. It is the drug of choice if it has been used by the mother in the past.
Unfortunately many doctors are, in my experience, still recommending that mothers should stop breastfeeding in order to take antidepressants. This may be that they think life would be easier if someone else could help with care of the baby or that the mother may get more sleep. Sadly, this doesnt always happen and the loss of oxytocin may also lower mood further.
There is often an assumption that pressure to breastfeed can lead to depression but in my experience pressure to stop breastfeeding in order to take medication may increase depression and may also stop mothers accessing professional help to avoid having that discussion.
This link to the RCGP perinatal mental health toolkit may be useful for professionals and parents
RCGP Mental Health Toolkit https://elearning.rcgp.org.uk/mod/book/view.php?id=13115
This factsheet contains information from my book Breastfeeding and Medication. Please message me for references used or with any questions.
See also https://breastfeeding-and-medication.co.uk/fact-sheet/depression-and-breastfeeding-2
https://www.breastfeedingnetwork.org.uk/factsheet/anxiety/
Citalopram | Drugs | BNF | NICE
“Specialist sources indicate that sertraline and paroxetine are the SSRIs of choice in breast-feeding based on passage into milk, half-life, and published evidence of safety. However, all SSRIs can be used in breast-feeding with caution, and since there are risks with switching an SSRI, it may be more clinically appropriate to continue treatment with an SSRI that has been effective, or restart treatment with an SSRI that has previously been effective. With all SSRIs, infants should be monitored for drowsiness, poor feeding, adequate weight gain, gastro-intestinal disturbances, irritability, and restlessness.”
https://www.ncbi.nlm.nih.gov/books/NBK501185/
https://www.e-lactancia.org/breastfeeding/citalopram/product/
citalopram and breastfeeding factsheet pdf

Citalopram is widely used by breastfeeding mothers.
It has a lower plasma protein binding than sertraline – less than 80% and the metabolite enters breastmilk in low levels. The manufacturer anecdotally reported cases of excessive somnolence, decreased feeding and weight loss in breastfed infants (Hale). However, more recent research suggests that symptoms are minimal and may not be associated with the use of this drug in lactation
There is one report of an infant exhibiting ‘uneasy’ sleep patterns on a maternal dose of 40 mg per day (Schmidt et al. 2000) that resolved when the mother’s dose was reduced and partial substitution with artificial formula undertaken.
Spigsett et al. (1997) studied two patients and estimated the absolute dose to the infant during steady-state conditions would be 0.7–5.9% of the weight-adjusted maternal dose.
Berle’s study (2004) of 25 women taking SSRI antidreprssants (nine taking citalopram) reported that no adverse effects on the babies were noted. The infant serum levels of citalopram were undetectable in four infants and low in the remaining six.
Lee et al. (2004) conducted a prospective, observational study of 31 mothers suffering from depression and taking citalopram with 12 mothers with depression but not taking citalopram and 31 healthy control women and babies. Mothers were taking up to 60 mg citalopram daily. There were numerically more reports of adverse events in the trial group 3 per 31 (depressed and taking citalopram group) compared with 1 per 31 (control group) and 0 per 12 (depressed but not taking citalopram group) but this was not a statistically significant difference. Infants of the mothers in the group exposed to citalopram reported colic, decreased feeding and irritability.
Heikkinen et al. (2002) studied 11 mother and baby pairs with matched controls, for up to 2 months after delivery. The neurodevelopment of the children was monitored for up to 1 year. The levels in infant plasma were very low or undetectable. The delivery outcomes and development were normal. Relative infant dose quoted as 3.6% (Hale).
References
- Berle JØ, Steen VM, Aamo TO, Breilid H, Zahlsen K, Spigset O, Breastfeeding during maternal anti-depressant treatment with serotonin reuptake inhibitors: infant exposure, clinical symptoms, and cytochrome P450 genotypes, J Clin Psychiatry, 2004;65:122834.
- Heikkinen T, Ekblad U, Kero P, Ekblad S, Laine K, Citalopram in pregnancy and lactation, Clin Pharmacol Ther, 2002;72: 184–91
- Lee A, Woo J, Ito S, Frequency of infant adverse events that are associated with citalopram use during breastfeeding, Am J Obstet Gynecol, 2004;190(1):21821.
- Schmidt K, Oleson OV, Jensen PN, Citalopram and breastfeeding: serum concentration and side effects in the infant, Biol Psychiatry, 2000;47:1645.
- Spigset O, Carieborg L, Ohman R, Norstrom A, Excretion of citalopram in breastmilk, Br J Clin Pharmacol, 1997;44(3):2958.
My book “Breastfeeding and chronic medical conditions” contains chapters on anxiety and depression
wendy@breastfeeding-and-medication.co.uk



Botox for medical purposes and Breastfeeding
Botox injections are used for many medical purposes including migraine, anal fissures. The amount of botox getting into milk is low based on the research on one mother who caught botulism from eating fermented salmon eggs. She continued to breastfeed. No botulinum toxin or botulism was found in the breastmilk or the baby. The doses that are used medically are far lower than that which would have caused the mother’s botulism so the amount in breastmilk is assumed to be too low to produce adverse effects.
Hale also comments that when Botox is injected into the muscle, it produces a partial chemical denervation resulting in paralysis of the muscle. When injected properly, and directly into the muscle, the toxin does not enter the systemic circulation. Thus levels in maternal plasma, and milk are very unlikely. Waiting a few hours for dissipation of any toxin would all but eliminate any risk to the infant. Also, avoid use of generic or unknown sources of botulinum toxin, as some are known to produce significant plasma levels in humans. (Hale TW Medications and Mothers Milk online version accessed Feb 2024)
In February 2024 a study of 4 mothers was published https://www.liebertpub.com/doi/abs/10.1089/fpsam.2023.0326
Objective: To detect the presence of botulinum toxin in breast milk from lactating subjects treated with facial botulinum toxin injections, as measured by enzyme-linked immunosorbent assay (ELISA).
Methods: For this pilot study, lactating women were injected with standardized facial botulinum toxin type A (BTXA) (range 40–92 U). Collected breast milk samples over 5 days were analyzed for the presence of botulinum toxin. Exclusion criteria included (1) lactating women still using their breast milk for their infant, (2) muscular disorders, (3) any medication that could interfere with neuromuscular function, (4) uncontrolled systemic disease, (5) pregnant, and (6) neuromodulator injection in the past 90 days.
Results: Four lactating women were recruited. Eight samples had no BTXA detected, whereas 8 of the 16 total had detectable amounts, which were well below the reported lethal oral dose for an infant.
Conclusion of the authors: Although the exclusion of lactating women from receiving cosmetic botulinum toxin injections is out of an abundance of caution to the theoretical risk to the infant, this study helps support the notion that facial botulinum toxin injections do not warrant an interruption in breastfeeding. Further studies with larger sample sizes are needed.
Hudson C, Wilson P, Lieberman D, Mittelman H, and Parikh S. Analysis of Breast Milk Samples in Lactating Women After Undergoing Botulinum Toxin Injections for Facial Rejuvenation: A Pilot Study.Facial Plastic Surgery & Aesthetic Medicine.ahead of print
See also https://infantrisk.com/content/botox-injections-and-breastfeeding (April 2025)

Botox and Fillers and Breastfeeding
There is no published research that I have been able to find and trust on the passage of fillers into milk so I cant say that they are safe or unsafe. I just do not know.
However InfantRisk IN USA set up by Tom Hale my guru, published this in April 20205 https://infantrisk.com/content/botox-injections-and-breastfeeding
There is some information from one mother who caught botulism from eating fermented salmon eggs. She continued to breastfeed. No botulinum toxin or botulism was found in the breastmilk or the baby. The doses that are used medically are far lower than that which would have caused the mother’s botulism so the amount in breastmilk is assumed to be too low to produce adverse effects.
In February 2024 a study of 4 mothers was published https://www.liebertpub.com/doi/abs/10.1089/fpsam.2023.0326
Objective: To detect the presence of botulinum toxin in breast milk from lactating subjects treated with facial botulinum toxin injections, as measured by enzyme-linked immunosorbent assay (ELISA).
Methods: For this pilot study, lactating women were injected with standardized facial botulinum toxin type A (BTXA) (range 40–92 U). Collected breast milk samples over 5 days were analyzed for the presence of botulinum toxin. Exclusion criteria included (1) lactating women still using their breast milk for their infant, (2) muscular disorders, (3) any medication that could interfere with neuromuscular function, (4) uncontrolled systemic disease, (5) pregnant, and (6) neuromodulator injection in the past 90 days.
Results: Four lactating women were recruited. Eight samples had no BTXA detected, whereas 8 of the 16 total had detectable amounts, which were well below the reported lethal oral dose for an infant.
Conclusion of the authors: Although the exclusion of lactating women from receiving cosmetic botulinum toxin injections is out of an abundance of caution to the theoretical risk to the infant, this study helps support the notion that facial botulinum toxin injections do not warrant an interruption in breastfeeding. Further studies with larger sample sizes are needed.
Caroline Hudson, Parker Wilson, David Lieberman, Harry Mittelman, and Sachin Parikh.Analysis of Breast Milk Samples in Lactating Women After Undergoing Botulinum Toxin Injections for Facial Rejuvenation: A Pilot Study.Facial Plastic Surgery & Aesthetic Medicine.ahead of print
References
1. Lee KC, Korgavkar K, Dufresne RGJ et al. Safety of cosmetic dermatologic procedures during pregnancy. Dermatol Surg. 2013;39:1573-86.
2. Middaugh J. Botulism and breast milk. N Engl J Med. 1978;298:343.
Both these cosmetic procedures have to be undertaken with this limited information in mind. It is your choice .
