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  • Writer's pictureDoctor Anastasia

Let's talk breastfeeding: what clinicians need to know

CASE #1: A 31 year old woman presents to A&E with severe secondary post-partum haemorrhage 3 weeks after giving birth. She is tachycardic and hypotensive but responds well to fluid resuscitation. While being prepped for theatre, the consenting anaesthetist informs her that she shouldn't breastfeed for 48 hours after the general anaesthetic. "Just to be on the safe side".

This case is pretty tough to talk about. See, that's me being wheeled to theatre, and that's my tiny exclusively-breastfed baby facing two days without a feed.

Luckily, I knew exactly where to access the evidence-based recommendations needed to reassure me and the anaesthetist that it would be safe to breastfeed post-op as soon as I was awake enough to do so. But another patient may not have felt as empowered to speak up. And the sad reality is that her breastfeeding journey may have ended for good that day.

I'm passionate about this topic for professional as well as personal reasons. As a Microbiology trainee, I've had numerous calls from clinicians asking for antimicrobial prescribing advice for lactating patients. For example:

CASE #2: A 28 year old patient with pyelonephritis, urine culture grows E. coli resistant to co-amoxiclav, sensitive to ciprofloxacin and tazocin. She is 10 days post-partum and her baby is exclusively breastfed. The clinician calling Micro wants to know if he should:

a) Give cipro, but withhold breastfeeding for a week, or

b) Admit for tazocin (even though the patient is well enough to be treated at home)

Now, this isn't an unreasonable phone call, but it reveals some important knowledge and skill gaps that I want to address today.

So, here are your KEY LEARNING POINTS for looking after a lactating patient:

1) The importance of breastfeeding

2) The impact of interrupting breastfeeding (especially in the neonatal period)

3) The FOUR steps to safe prescribing for lactating patients:

A) Think about it => pharmacology & physiology

B) Look it up => reliable prescribing guidance

C) Talk to the patient => risk assessment and decision

D) Access support => for you and the patient

1) The importance of breastfeeding

The World Health Organization recommend that all babies are breastfed exclusively for 6 months, and that breastfeeding continues alongside solids until at least 2 years. Breastfed infants experience a decreased risk of respiratory and diarrhoeal infections, sudden infant death, asthma, atopy, and obesity, while breastfeeding reduces maternal risk of breast and ovarian cancer, osteoporosis, cardiovascular disease and obesity. Breastmilk is nutritionally complete and immunologically active: it contains immunoglobulins, cytokines, chemokines, growth factors, extra-cellular vesicles and hormones. These are not only vital to preventing infection in infants, but also to establishing immunological tolerance (and hence reducing downstream inflammatory illnesses). The microbes in breastmilk are increasingly recognised as playing a critical role in establishing the infant's gastrointestinal and upper respiratory microbiome. The human milk oligosaccharides (HMOs) found in milk are indigestible by the infant; rather, they feed favourable resident gut bacteria (e.g. Bifidobacterium), and inhibit pathogens (directly and indirectly). The benefits of breastfeeding are so profound that increasing global breastfeeding to near universal levels could reduce under-5 mortality by 823,000 deaths per year, and prevent 20,000 maternal deaths per year.

2) The impact of interrupting breastfeeding

Despite these benefits, the UK has one of the lowest breastfeeding rates in the world, with only 1% of women exclusively breastfeeding to 6 months post-partum. The reasons for this are complex and beyond the scope of any individual clinician to tackle. But make no mistake: the odds are already stacked against a new mother trying to breastfeed, and the last thing she needs is an additional potentially-avoidable hurdle. During the first few weeks, each and every feed plays a crucial role in establishing milk supply and infant latch. So imposing an interruption of days or even weeks could mean that she is never able to continue breastfeeding.

3) The FOUR STEPS to safe prescribing for lactating patients

The safety of mother and infant are paramount, and (clearly) the answer is not to disregard safety concerns and prescribe as if she were not lactating. But withholding breastfeeding "just to be on the safe side" erroneously assumes that the impact of stopping breastfeeding is negligible - hopefully, the sections above have firmly convinced you otherwise.

So, what should you do?

A) Think about it. When in doubt, go back to first-principles: in this case, pharmacology and physiology. Although pregnancy and breastfeeding are often lumped together, the risk of trans-placental drug exposure is far higher (for most drugs) than via milk. Generally, two groups of drugs are most likely to cause issues (and are therefore justifiably contraindicated) in breastfeeding women:

  • Drugs that achieve high concentrations in milk (e.g. lithium, amiodarone). These are often highly lipid-soluble drugs with low maternal plasma protein binding.

  • Drugs with very high inherent toxicity, even if concentration in milk may not be high (e.g. cytotoxics, isotretinoin).

Additionally, concerns regarding drugs in breastfeeding can arise when:

  • There is evidence of harm using animal models.

  • There is absence of any safety data in breastfeeding.

However, in both of these cases, the potential risks must be weighed against the risks of withholding breastfeeding or using second-line treatment options in lactating women.

B) Look it up. These are the most reliable sources of information:

  • The Breastfeeding Medicines Advice Service (UKDILAS), part of the UK Specialist Pharmacy Service. This offers drug-specific advice, a template for conducting a risk assessment with the mother's involvement, and a phone/email support service.

  • LactMed, from the US National Library of Medicine. Thorough, reputable, and up-to-date.

Specialist Pharmacy Service website banner: Advising on medicines during breastfeeding

"Most medicines can be used throughout breastfeeding, in some cases further risk-reducing methods may be required" - UKDILAS

There are many other excellent resources, but an important caveat for each one:

  • The British National Formulary (BNF) and equivalent formularies in other countries: largely based on the drug's Summary of Product Characteristics (SmPC), which is the legal document approved as part of marketing authorisation for each drug. As such, the threshold for recommending a drug in breastfeeding is very high and the advice is necessarily cautious, which may lead to prescribers incorrectly inferring that a drug is not safe for use in breastfeeding. Indeed, the UK national guidelines (NICE) advise that the BNF should only be used as a guide for prescribing during lactation, and that individual decisions should be based on reference to LactMed and/or UKDILAS.

  • The GP Infant Feeding Network has a useful overview of prescribing in breastfeeding, and excellent resources on infant feeding in general. However, it doesn't offer drug-specific advice on prescribing.

  • The Breastfeeding Network is a charity offering fantastic resources on infant feeding and supporting mothers, including leaflets for parents. There are also excellent drug-specific prescribing resources, although they note that their guides cannot replace input from a professional.

GP Infant Feeding Network website banner: GPIFN over a breastfeeding infant

C) Talk to the patient. Even with the fantastic resources above, the ultimate decision to prescribe a drug to a lactating patient will come down to an individualised risk assessment. And that assessment MUST include the woman's own risk perceptions and tolerance.

(Reminder: UKDILAS has a fab printable template for conducing the risk assessment)

D) Access support. When you cross paths with a lactating patient, it's easy to focus only on a particular clinical problem, e.g. an infection or surgical site complication. But each encounter with a lactating patient is a valuable opportunity to ASK how she is getting on with breastfeeding and direct her to support as needed:

  • In your own organisation: Make sure you know WHO to turn to for breastfeeding support, e.g. a designated midwife or health visitor.

  • In your local community: La Leche League is an international charity with branches in many countries. They offer free online or face-to-face support groups for breastfeeding mothers.

  • On the phone: If you're practicing in the UK, you can contact the National Breastfeeding Helpline on 0300 100 0212 (9.30am to 9.30pm, daily).

  • Online: Unicef's Baby Friendly Initiative has amazing resources for parents and healthcare professionals.

Final thoughts

I don't remember ever being taught any of this at medical school or during my training as a junior doctor. Then three things happened which completely transformed how I view my role as a clinician caring for lactating patients:

1) I started my PhD, researching the microbiome in the perinatal period. I was utterly blown away by the science on breastfeeding, highlighting its critical role in child health.

2) I began my own breastfeeding journey as a mother, and experienced firsthand how valuable the support and resources above can be.

3) I became certified as a Breastfeeding Peer Supporter. This training was such an empowering opportunity to gain knowledge and skills outside of my usual clinical role, and served as the impetus for creating this teaching resource for fellow clinicians and students.

Caring for patients at the start of their parenting adventure is a wonderful privilege. I really hope you found these tips helpful, and that you can implement them into your own practice to better support new mums and their infants. Please share this with your colleagues today, and subscribe to Hello Micro so that I can send you more high-yield Microbiology resources!


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