Author: Elise Armoiry, IBCLC, pharmacist
Author Information and Disclosure of Conflicts of InterestAbstract
Pregnancies in transplant recipients are becoming increasingly frequent, highlighting the need for lactation consultants to be well-informed about the compatibility of immunosuppressive treatments with breastfeeding. This paper presents a synthesis of current knowledge on the safety of these medications during lactation, along with a case report of a breastfeeding consultation for a woman with cystic fibrosis who had undergone both liver and lung transplants and had cystic fibrosis related diabetes mellitus.
The patient sought a prenatal consultation at 25 weeks of gestation with the author, a private lactation consultant and former hospital pharmacist. A targeted literature review was conducted to assess the compatibility of her post-transplant medications with breastfeeding. Based on this review, a personalised prenatal consultation was provided. Follow-up consultations were conducted at 6 days and 1 month postpartum. At 5 months of age, the infant was still exclusively breastfed.
Access to accurate, medication-specific information enabled the patient to make an informed decision regarding breastfeeding. While breastfeeding in the context of organ transplantation and cystic fibrosis remains rare, this case demonstrates that it is feasible. Multiple sources in the literature support the possibility of breastfeeding while on immunosuppressive therapy.
Keywords: breastfeeding, organ transplantation, immunosuppressive therapy, cystic fibrosis, case report
How to cite: Armoiry E: Breastfeeding consultation in organ transplantation recipients: Theoretical background and a case report. Lactation & Breastfeeding 2025;4:03.
1. Breastfeeding after organ transplantation
Breastfeeding has many benefits, both for the mother and the child, and most health organisations recommend exclusive breastfeeding for at least 6 months of life, and then, alongside the introduction of adequate complementary solid foods, for 2 years or until the mother or the child decides to wean (World Health Organisation; Lancet, 2016).
Organ transplantation is a life-saving procedure when there is an organ disease. It involves the recipient undergoing lifelong immunosuppressive therapy, allowing the body to accept the graft. More and more pregnancies appear to happen in female transplant recipients. The Transplant Pregnancy Registry International (TPRI) is a worldwide organisation whose aim is to study the outcomes of pregnancies in transplant recipients. In their 2022 annual report, 3875 pregnancies in female transplant recipients have been reported in 37 countries (TPRI, 2022).
Breastfeeding after organ transplantation remains an uncommon situation, with possible confusion as most immunosuppressive medications have a label that does not recommend breastfeeding. It used to be contraindicated because of the immunosuppressive treatment, but there are now compatible treatments, even if for some drugs, breastfeeding is still discouraged due to the lack of toxicity information.
Breastfeeding rates are rising in this population: from <10% in the early 1990s, to 35% in 2012, and up to 80% more recently (TPRI, 2022) (Fig. 1).
In their 2022 report, the TPRI shows the paradigm shift regarding breastfeeding trends around 2015: breastfeeding then became predominant, with the number of recipients breastfeeding greater than those not (Fig 1). It follows a 2014 publication from the TPRI team in a medical journal regarding Breastfeeding after an Organ Transplant (Constantinescu, 2014). In 2022, there were 826 infants whose mothers reported breastfeeding for some time while on immunosuppression, from a few days up to 4.5 years.
1.1 Immunosuppressive therapy and transfer of immunosuppressive drugs into breast milk
Transplant recipients will follow an extensive treatment with a combination of several drugs to prevent organ rejection and maintain graft tolerance. These medicines will vary depending on the organ transplanted. There is usually an induction treatment followed by a maintenance treatment as long as the transplant is functioning.
For mothers on immunosuppression therapy, breastfeeding also has the side effect of exposing the child to immunosuppression, after an exposure in utero during the pregnancy.
In order to transfer into the breast milk, and then to the infant, medications must have certain pharmacokinetic properties. Most drugs will transfer through passive diffusion: an active agent with a small molecular weight, poor protein binding, a low volume of distribution, and highly lipophilic component will transfer more easily compared to a large hydrophilic component.
The half-life[1] and metabolism pathway will also be of interest. A parameter often used to assess drug toxicity is the relative infant dose (RID), which compares the theoretical infant dose – based on breast milk concentration and volume consumed – to the maternal dose. When it is below 10%, it is considered safe.
Only 4 immunosuppressive medications are considered safe with breastfeeding:
- Azathioprine:
It has a low molecular weight of 277 and a high pKa[2] of 8.2: suggesting a high bioavailability in breast milk. However, McKinzie et al. report “RID of azathioprine is estimated to be 0.07–0.3% with maternal doses of 0.5–2 mg/kg/day of azathioprine, suggesting limited infant exposure. Clinically, this appears to be the case as reported in both transplant and autoimmune populations, which reported undetectable infant concentrations in a majority of neonates and infant exposure estimated at < 0.09% of the maternal dose.” (McKinzie et al., 2022)
Azathioprine is used as a second-line treatment because mycophenolate has better tolerability and efficacy. However, being an older drug, we have more information on azathioprine regarding breastfeeding and breastfeeding is considered acceptable (Constantinescu et al., 2014; Anderson, 2020; TRPI, 2022).
The Lactmed database suggests avoiding breastfeeding for 4 hours after a dose, which might decrease the exposure through breast milk (NIH, 2025). Indeed, in the first four hours after the dose, there might be an increase in metabolites with potential toxicity. However, the clinical impact on the infant is not clear (Singh et al., 2011).
- Cyclosporine
It is the oldest antirejection drug in this class but is no longer a first-class drug. The pharmacokinetic properties suggest low transfer into milk (high protein binding), and it has poor absorption (low oral bioavailability) which means that the dose absorbed by the infant would be minimised. The infant would receive about 2% (and often <1%) of the mother’s weight-adjusted dose. It is generally not detectable in the infant’s blood. Anderson reports that this drug has been used in numerous breastfeeding mothers and no reports of side effects on infant growth, development or kidney function has been made. However, Anderson suggests a monitoring of infants, possibly with serum concentration (Anderson, 2020). A Polish study published in 2020 (Kociszewska-Najman et al., 2020) reports low transfer of cyclosporin and its metabolites in colostrum. It is considered safe to use during breastfeeding (Constantinescu et al., 2014; Anderson, 2020; TRPI, 2022).
- Tacrolimus:
Tacrolimus is the first-line antirejection treatment for most transplants.
Pharmacokinetic factors of tacrolimus are as follows: a high protein binding capacity, large molecular weight, and low bioavailability, which suggests low potential for transfer into human milk. Estimates of the ingested dose are 0.06%–0.5% of the maternal weight-adjusted dose. Mc Kinzie et al. state “Nearly all studies have shown that concentrations of tacrolimus in infant blood are below detection limits, and assuming a worst-case scenario based on maximum concentrations, the estimated infant exposure via milk is typically <1% of maternal concentrations”. It is considered acceptable to use during breastfeeding (Constantinescu et al., 2014; Anderson, 2020; TRPI, 2022).
- Corticosteroids: Prednisone, Methylprednisolone
They are used for induction, maintenance, and treatment of acute rejection. They transfer into breast milk, and Constantinescu explains that “exposure from breast milk remains at most 0.1% of total maternal dose of prednisolone, which is also <10% of the endogenous corticosteroid production by an infant“ (Constantinescu, 2014). It is generally not detectable in the infant blood. It is considered safe to use during breastfeeding (Constantinescu et al., 2014; Anderson, 2020; TRPI 2022).
Anderson explains that antirejection drugs that are compatible with breastfeeding should be used with caution in newborns or preterm infants (Anderson, 2020). Other drugs are not recommended, often more by lack of information than by recognised toxicity.
Klein & Josephson aptly highlight an important point when stating “Without dismissing the potential significance of immunosuppression exposure, decisions regarding whether to breastfeed should consider that the infant’s exposure to immunosuppression with breastfeeding is lower than in utero exposure” (Klein & Josephson, 2022).
1.2 Impact of immunosuppressive treatment on lactation
For treatments compatible with breastfeeding, it is also important to consider their potential effect on milk production.
On this subject, information is not available for cyclosporine, but the Lactmed database provides the following information for the other drugs.
- For Prednisone, medium to large doses of corticosteroids given systemically or injected into joints or the breast have been reported to cause temporary reduction of lactation.
- For Azathioprine: Cases of hyperprolactinemia and galactorrhoea with normal prolactin have been reported rarely.
- For Tacrolimus: There might be reduced prolactin, but the prolactin level in a mother with established lactation may not affect her ability to breastfeed (NIH Lactmed, 2025).
We can also point out that treatments requiring hospitalisation (e.g., intravenous antibody administration in hospital) may affect breastfeeding if the child is not allowed to stay with the mother.
1.3 Outcomes of pregnancies and children born to female transplant recipients after exposure to immunosuppressive treatment
After organ transplantation, pregnancies are at high risk: there are more premature births and there is a risk of low birth weight. For renal transplantations, the rates of preeclampsia, gestational diabetes, caesarean section, and pregnancy-induced hypertension are increased (Shah et al., 2019). Those conditions might have an impact on the breastfeeding journey.
McKinzie et al. also report early effects of the immunosuppressive treatment in the infant (due to exposure in utero), including renal dysfunction from calcineurin inhibitors, myelosuppression from azathioprine, and decreased circulating immune cells with several agents. These effects appear from birth and are temporary but the decrease in immune cells may predispose the infant to increased infectious complications in the first year of life (McKinzie, 2022).
In the TPRI 2022 report, the long-term outcomes of children exposed to immunosuppressive treatment during pregnancy and breastfeeding are presented. Median follow-up was 15.3 years (6.8–23.5 years), and most of the children were reported as healthy by their mothers at the last follow-up (74%). Despite a high rate of low birth weight and prematurity, the authors report normal long-term development. The most common diagnoses were asthma, allergies, and renal diseases (due to anatomical deformation).
1.4 Level of knowledge of health professionals about breastfeeding during immunosuppression
The historical understanding and advice from health professionals regarding breastfeeding during immunosuppression has significantly evolved. Klein & Josephson report a 2002 study in which 67% of providers advised female recipients of transplants to avoid breastfeeding (Klein & Josephson, 2022). But in 2003, the American Society of Transplantation explained that breastfeeding should not be viewed as absolutely contraindicated, and in 2014, the TPRI released an article on breastfeeding after transplantation (Constantinescu, 2014). We can see that breastfeeding is more and more common in this population since 2015.
Despite these advancements, recent studies highlight persistent gaps in the practical knowledge and consistent guidance provided by health professionals.
Sadonikova et al. present a retrospective cohort study of 35 women with chronic kidney disease, with or without kidney transplantation, who gave birth at a tertiary health system between 2010 and 2020. Patients on immunosuppression were more likely to exclusively formula feed (p = 0.02) or to initiate breastfeeding and then switch to formula (p = 0.0004) because of their immunosuppressive medications, versus patients on any other medication (Sadonikova, 2023).
The authors report on the patients’ claims: non-evidence-based medication advice – especially when discussing use of immunosuppressive therapy or antihypertensive agents, lack of a singular physician specialty leading the medication management, and unsustainable or non-supportive lactation routines.
Multiple physicians in this study instructed patients to ‘‘pump and dump until the safety of medications is figured out’’; notably, this was the recommendation on day 1 postpartum for all patients with a kidney transplantation who desired to breastfeed, which led to stopping breastfeeding due to the pumping schedule and lack of sleep.
Health professionals’ guidance on breastfeeding under immunosuppression has evolved toward greater acceptance since the early 2000s, yet recent studies reveal persistent gaps, with many transplant recipients still receiving inconsistent, non–evidence-based advice that often discourages or disrupts breastfeeding.
1.5 Level of knowledge of women about breastfeeding with an immunosuppressive treatment
In a 2024 study Korzeb et al. report a cross-sectional survey on 28 women of reproductive age who received a kidney transplant and 17 liver recipients. This survey consisted of single or multiple-choice questions to evaluate women regarding their knowledge on breastfeeding after an organ transplantation (Korzeb et al., 2024).
Questions included breastfeeding benefits. The authors considered the participants’ knowledge to be low, and benefits for the baby appeared to be more commonly known than breastfeeding benefits for the mother. 82% of women were concerned about possible harm to their babies from immunosuppressive treatment transferred through breast milk. Regarding future decisions, 22% indicated that they would not breastfeed during immunosuppressive treatment, whereas 78% said they would breastfeed if the safety was confirmed.
De Filippi et al., in a 2024 article, report on patient perceptions and knowledge surrounding pregnancy after heart transplantation. A survey was sent to 317 women who were heart transplant recipients, of whom 64 responded. Of these, 61% were unsure if breastfeeding was considered safe after a heart transplant, 25% reported that breastfeeding was not safe, and 14% felt breastfeeding was safe. The authors point out medication during breastfeeding as a future area of education for the transplant recipients (De Filippi et al., 2024). Those studies show the importance of healthcare professionals to educate women regarding the compatibility of their treatment and breastfeeding. There is limited research on transplant recipients and lactation education, and more studies on breastfeeding experience among transplant recipients are needed.
Case-report: breastfeeding consultation in a liver-lung transplantation recipient with cystic fibrosis
The patient is a 32-year-old woman with cystic fibrosis and had cystic fibrosis related diabetes. She received a liver and lung transplant in 2012 in France.
In March 2020, the patient reached our private lactation practice for a prenatal lactation consultation. She was 25 weeks pregnant and wanted specific information regarding the compatibility of her medications with breastfeeding. She wanted to know if there were any contraindications to breastfeeding with her immunosuppressive treatment, especially because she had received conflicting information on the subject. Indeed, the French drug database on pregnancy and breastfeeding drug toxicity (www.lecrat.fr) was quite reassuring, whereas one of her healthcare professionals assumed that she would not breastfeed because of her medications.
The consultation took place via telehealth, due to the COVID-19 pandemic, and a written report was sent by email following the consultation. The patient was extremely motivated and had already read 2 books about breastfeeding and breastfeeding a premature baby, as her pregnancy was considered high-risk.
2.1 Compatibility check
The lactation consultant has a background as a hospital pharmacist. The treatments at the time of the consultation consisted of: Prednisone 5 mg/day, Advagraf 15 mg/day (tacrolimus), Imurel 100 mg/day (azathioprine), Eupantol 40 mg/day (pantoprazole), Zithromax 250 mg, 3 times/week (azithromycin), Aerius 5 mg/day (desloratadine), Alvityl 1/week (vitamins), Uvedose 1/month (vitamin D), Créon 2500 U, 2/day (pancrelipase), Mag2 100 mg/day (magnesium carboxylate), Toco 500 mg, 2/day (Vitamin E alpha-tocopherol), Ascofer 33 mg/day (iron), and insulin.
Three compatibility databases were consulted for compatibility: Hale’s Medications and Mothers’ Milk Manual (2019), e-Lactancia (APILAM) and Lactmed (NIH). The French database “Le Crat” (Le Crat, 2025) was not used, as it seems to be less regularly updated than other resources. All 3 databases report no contraindication for the patient’s medications during lactation, especially regarding the immunosuppressive treatment: prednisone, tacrolimus and azathioprine. Regarding long-term corticosteroid use, the increased risk and signs of postpartum depression were discussed. Indeed, chronic corticosteroid therapy is associated with an increased risk of mood disturbances, including depression. Corticosteroids influence serotonin and dopamine pathways, alter hypothalamic–pituitary–adrenal axis regulation, and may induce hippocampal and prefrontal cortex changes that affect mood regulation. In the postpartum period, these neuroendocrine effects can compound the physiological and psychological stressors of childbirth, heightening vulnerability to postpartum depression.
2.2 Literature analysis on breastfeeding after a transplant or with cystic fibrosis
The lactation consultant also conducted a literature analysis. Most articles and guidelines reported compatibility of immunosuppressant drugs with breastfeeding (Anderson, 2020; British Transplantation Society, 2017; Paizis, 2019; Cimino et al., 2016; Hammoud et al., 2013; Deshpande et al., 2013; Kroon et al., 2018; Watson et al., 2019). They also recommended monitoring, which could include drug blood testing in the child (Cimino et al., 2016; Despande et al., 2013; Kroon et al., 2018 ), or testing of breast milk (Watson et al., 2019) or blood counts (Anderson, 2020), or hepatic function surveillance (Kroon, 2018).
Delaying the feed after the dose was sometimes recommended (Kroon, 2018).
The American Academy of Family Physicians and other authors (Cimino et al., 2016; Deshpande et al. 2013) stated that breastfeeding benefit outweighed the risk of drug exposure through breast milk.
As stated by Watson et al. in 2019, the longer-term follow-up of breastfed infants is important to improve understanding of the long-term effect of exposure to immunosuppression in human milk. The author encouraged the patient to discuss her breastfeeding plan further with the maternity team and to contact patients’ associations to seek testimonies from women with the same condition who had breastfeeding experience. Regarding immunosuppressive treatment, the lactation consultant suggested discussing the available data with the hospital team and, if necessary, to propose the following recommendations found in several papers: measuring the drug levels in the infant for tacrolimus, and, if appropriate, avoiding breastfeeding for 4 hours after the azathioprine dose to decrease drug transfer. In that case, if the immunosuppressant was taken in the evening, the mother could pump during the day and breastfeed in the evening just before taking her medication. She would then wait 4 hours before the next feed but would still have expressed milk available if needed.
2.3 Lactation prenatal information
In addition to the targeted information regarding those treatments, the usual prenatal information about breastfeeding was delivered. It included information regarding the first feed after birth, infant feeding cues, infant feeding pattern, breastfeeding positions and latch, milk expression, and how to prevent and manage common difficulties. Because of the mother’s condition, specific information was provided regarding premature birth, sleepy and low-birth-weight babies, and milk-pumping. Because of her diabetes, the possibility of hypoglycaemia after birth was explained, and the methods to give supplements, if needed, were explained. The importance of dietary support was emphasised (Durieu, 2003; HAS, 2017). Due to the specificity of the condition, this was already in place. The author suggested adding snacks for the mother before the feeds, on-hands snacks if the feed was longer than expected, and more consistent dinners (because of the night feeds).
2.4 Birth and lactation postpartum information
The birth took place at 38 weeks of amenorrhea by elective caesarean section, as a vaginal birth posed a risk of respiratory insufficiency given the mother had only one lung. The infant was 2,960 kg at birth, with the lowest weight being 2,690 kg and weight fluctuation during more than 1 week which led to supplementation with formula and the mother’s breast milk. There was no hypoglycaemia in the infant. Direct breastfeeding was temporarily suspended at day 2 for 3 days following a high tacrolimus residual dosage in the baby’s plasma. Most of the tacrolimus in the infant’s circulation at birth reflects placental transfer, not milk ingestion. The mother pumped her milk every 3 hours and dumped it during those 3 days. In the first 2–4 days postpartum, mammary tight junctions are open, meaning more serum components (including medications) can diffuse into milk. As lactogenesis II occurs, junctions close, and transfer of most drugs decreases markedly. Therefore, in those early days, tacrolimus levels in milk may be transiently higher – this is why the mother was advised to pump and dump. The milk expressed during those first 3 days should not be stored for later use. The tacrolimus concentration may indeed be higher, mirroring maternal plasma levels while the paracellular pathways are open.
Supplementation by formula was given by the father with a syringe. The patient asked the lactation consultant for support by email on day 6, and information regarding breast compression, hands-on pumping, supplementing, cracked nipples, and self-care was provided. A follow-up was provided at 30 days by email with information regarding positioning because there was still nipple pain (breast milk was pumped periodically and given to the baby to allow the nipple to heal). The nipple pain resolved at 6 weeks. The last follow-up was performed at 5 months: The baby was still successfully breastfed with no particular adverse reaction. No drug concentration measurements in plasma or blood count (to monitor potential immunosuppression) were performed in the infant regarding his mother’s medication.
Conclusion
Specific information regarding drug compatibility and breastfeeding enabled the patient to make an informed choice about breastfeeding and to feel confident advocating for her breastfeeding choice with the hospital team if needed. As she stated: “Thanks to our consultation during pregnancy, I had the right information regarding my breastfeeding options with my treatments. During my pregnancy and birth, I had very few choices. Breastfeeding was a strong and obvious need. But the choice was never mine since everything depended on taking my medications into account. Your recommendations guided me until my delivery, where I was prepared to present them if someone told me I could not breastfeed. In the end, other than this residual level of tacrolimus, no one questioned the possibility of breastfeeding my baby, but I don’t know if it was through lack of training or deliberately. I do not think that we have enough examples of mothers with both transplant AND cystic fibrosis in any department.“
Although breastfeeding after an organ transplantation is not common, it is possible. Several literature resources report cases of women breastfeeding while on immunosuppressive medications. The lactation consultant plays an important role in providing information regarding the transfer of medications into breast milk, and up-to-date breastfeeding data in the context of transplant-associated high-risk pregnancies. More research is needed regarding the medication education in this population, as significant gaps remain in knowledge and guidance for both health professionals and patients.
[1] Half-life: The elimination half-life is defined as the time required for the concentration of a specific substance, typically a drug, to decrease to half of its initial amount in the body. 94% to 97% of a drug is eliminated after 4 to 5 half-lives.
[2] pKa is a measure of the tendency of a molecule or ion to keep a proton, H+ , at its ionization center(s). It is related to the ionization capabilities of chemical species. In biological terms, pKa is thus an important concept in determining whether a molecule will be taken up by aqueous tissue components or the lipid membranes.
Elise Armoiry is a pharmacist with a background as a hospital consultant in geriatric hospitals. She has been an IBCLC for 6 years.The author declares that she has no conflicts of interest or financial relationships with commercial products.