Issues with breastfeeding

Breastfeeding can be difficult for many mothers – physically and mentally. This can see some parents resign themselves to exclusively formula feeding their child. Others try mixed feeding, offering their child as much breast milk as possible before supplementing with infant formula as needed.^1,5

Common breastfeeding complications include:

• Sore nipples, blocked ducts, and painful or bleeding nipples.² Nipple soreness is common – particularly in early breastfeeding,⁵ and is one of the most common reasons mothers decide to stop breastfeeding.⁵
• Mastitis. Inflammation of the breast, causing flu-like symptoms and pain.¹ Around 10-25% of breastfeeding mothers will experience mastitis at least once, more commonly with their first child, and in their early days of breastfeeding.⁵
• Inverted/flat nipples. This can make it challenging to offer the breast to an infant.^1,5
• Difficulty attaching the baby to the breast.¹
• Nipple vasospasm. Blood vessels in the nipple spasm, interfering with normal blood flow.¹ – Engorgement. Swelling of the breast as milk production increases after birth, which can cause discomfort or pain if not managed properly.⁵
• Dermatitis and eczema.⁵ This can affect the nipples or breasts.

While some mothers experience difficulties when beginning to breastfeed, these can often be overcome or resolved with the support and advice of healthcare professionals.⁵

Low breast milk supply

Many mothers feel they’re unable to produce an adequate supply of milk, causing 25-35% to decide to reduce the duration or amount they breastfeed.⁵ However, this is often a perception – only rarely (mostly due to illness) are parents actually unable to produce the amount of milk their child needs.⁵ In these cases, providing reassurance and explaining how to identify whether an infant is feeding well can be helpful to ensure milk supply increases.^5,6

Remind mothers that the most effective way to ensure an adequate milk supply is to feed often.¹ Should their low supply continue to cause serious problems with feeding, adopting a mixed feeding approach still provides many of the natural benefits of breastmilk to their baby.⁷

Baby with low weight

When an infant is born prematurely (earlier than 32 weeks), or of a low birthweight (<2500 g), they have increased nutritional needs and are more vulnerable to infection.⁵ As a result, they may require breast milk which has been fortified with key nutrients including protein, calcium and zinc.⁵ These nutrients are supplied by some infant formulas.

Offering expressed breast milk or properly prepared infant formula can also reduce the risk of vulnerable infants being exposed to infection while they remain in a neonatal intensive care unit.¹ In other cases, parents worry their baby isn’t gaining enough weight (or has lost weight).¹ As a healthcare professional, you may decide to recommend mixed feeding to these parents – temporarily until the infant’s slow weight gain is resolved, or ongoing.

Infant illnesses or conditions

Infants born with rare metabolic disorders such as galactosaemia, maple syrup urine disease and phenylketonuria (PKU) are unable or severely limited in their ability to breastfeed.⁵ These conditions require special infant formulas catering to the distinct needs and restrictions they entail.⁵

Maternal illnesses or conditions

Various illnesses can affect a mother’s ability to breastfeed. – Post natal depression can make breastfeeding difficult and interfere with the relationship between mother and child after birth.⁵ While some antidepressant medications appear safe to use while breastfeeding, other treatments for post natal depression can leech into breast milk, with unknown consequences for infants feeding on the affected milk.⁵ Some medications may also interfere with normal milk production.¹ Despite this, successfully learning to breastfeed can improve a mother’s self-esteem and mood and help the mother bond with her child.⁵ While breastfeeding mothers experiencing post natal depression need professional support throughout this time, continuing breast or mixed feeding can have positive outcomes for both mother and baby.⁵

• Experiencing a stressful birth may interfere with the normal release of oxytocin – a hormone required for breast milk supply.⁵
• Maternal type 1 diabetes can delay breastfeeding or make it more difficult^.5
• Maternal obesity has been linked to delays in initiating breastfeeding, and to ceasing breastfeeding sooner.⁵ While the exact reasons for this are unknown, most mothers with obesity can learn to breastfeed normally with professional support.⁵
• Maternal substance or alcohol use and HIV make breastfeeding off-limits.5
• Other circumstances can temporarily interfere with breastfeeding, including severe illnesses like sepsis, HSV-1 and the use of specific medications.5 Lifestyle changes

There are various practical reasons why parents may choose to adopt a mixed feeding approach. These include:

• Returning to work. Many mothers return to work before they’re ready to stop breastfeeding. While some manage to continue breastfeeding after returning to their job, others can’t or prefer not to.²
• Flexibility. Some parents find mixed feeding offers greater flexibility and fits into their schedule more easily compared to breastfeeding.
• Caregiver involvement. Some infants are cared for by people other than their primary parents, including grandparents, extended family members, friends and early childcare workers.
• Feeling uncomfortable breastfeeding in public. Some mothers feel a level of discomfort about breastfeeding in public settings.² Whether this begins in the early days of breastfeeding or becomes more consuming as they begin to spend time outside the home again, mixed feeding can help to alleviate this discomfort.

Many of these breastfeeding complications can be resolved or improved with guidance, support and patience.⁵ This may allow mothers to return to exclusive breastfeeding if they choose, or to continue breastfeeding alongside formula feeding if appropriate.⁵

Breast milk and infant formula compositions

Human breast milk is a complete and optimal source of nutrition for most infants throughout their first months of life.⁸ Breast milk uniquely contains numerous essential nutrients and other components which support the healthy growth and development of infants and work together to promote a healthy gut microbiota and immune system,⁸ including:

Water, which makes up around 88% of breast milk’s volume,⁹ meaning breast milk alone can provide all an infant’s fluid requirements for at least their first 6 months of life.⁵

• Antibodies, including immunoglobulin A (IgA), which help protect infants against infection.¹⁰
• Enzymes which support digestion and nutrient absorption.^9,10 – Essential fatty acids, including DHA, which are essential for healthy brain development.¹⁰ – Human milk oligosaccharides (HMOs) and beneficial probiotics, both of which contribute to the development of a healthy, balanced gut microbiota^9,10 – which is crucial for healthy immune system maturation in infants.¹⁰
• As well as proteins, fats, vitamins, minerals, nucleotides, hormones and more.^9,10

The presence of and interactions between these components create many of the unique benefits of breast milk.¹¹ The properties of breast milk help to establish a healthy and balanced gut microbiota in infants – which is essential for the development of a resilient immune system.⁵ The composition and diversity of an infant’s gut microbiota has long-term implications for their health and immunity, and impact their risk of allergy, infection and other health conditions.¹²

Probiotics and prebiotics naturally contained in breast milk stimulate the growth of beneficial bacteria in the gut, therefore playing a crucial role in protecting infants against harmful pathogens, bacteria and disease and supporting their healthy immune system development of infants.^13-16

A key differentiator between different infant formulas is whether or not they contain prebiotic oligosaccharides, which closely mimic the functional benefits achieved by human milk oligosaccharides (HMOs) naturally found in breast milk.¹⁴ Formulas supplemented with specific prebiotic oligosaccharides including short chain galacto-oligosaccharides (scGOS) and long chain fructo-oligosaccharides (lcFOS), may help establish a gut microbiota in formula-fed infants which more closely resembles that of a breastfed infant.^13-17 These prebiotics can reach an infant’s intestine undigested, where their bifidogenic effects selectively fuels the growth of beneficial bacteria strains (particularly species of Bifidobacterium and Lactobacillus) to promote a balanced, healthy microbiota.^12,18,19 In this way, prebiotic oligosaccharides can mimic some of the functional benefits of breast milk to help support immunity in formula-fed infants.^12,18,19

Mixed feeding, or the combination of breast and formula feeding, also impacts the colonisation, balance and health of an infant’s gut microbiota. While a breastfed infant’s microbiota is generally dominated by Bifidobacterium (transferred through breastfeeding),²⁰ formula-fed infants tend to have a more diverse gut microbiota,^21-23 s which is why it’s essential to recommend the right formula when mixed feeding. Mixed feeding will likely establish a different microbiota composition in infants yet again.²²

The specific impact of mixed feeding on an infant’s gut microbiota and health outcomes will vary depending on the infant, the formula used, and the frequency and duration of mixed feeding. Studies show any amount of breast feeding is beneficial for the infant’s health outcomes and wellbeing.⁵

Why maintain breastfeeding when introducing infant formula??

Research shows there are significant differences between the gut microbiota of infants who are exclusively breastfed, and exclusively formula-fed.¹⁹ The microbiota of breastfed baby or infant is rich in bacterial species which have been linked to positive brain development and function, while the microbiota of exclusively formula-fed infants contains bacterial strains which can negatively affect cognitive development.¹⁹

Extensive research supports the importance of breastfeeding – even in combination with formula-feeding – for optimal infant brain development and function.^5,19 Breastfeeding (including as part of mixed feeding) changes the composition of an infant’s gut microbiota, fuelling the growth of specific bacterial species which support brain development and cognitive function.^18,19

For some parents exclusive breastfeeding isn’t possible, however this doesn’t mean they should abandon the idea of breastfeeding altogether. If parents can adopt a mixed feeding approach, their child will still experience many of the unique benefits of breast milk.⁵

Preparing parents for mixed feeding: a step-by-step guide

Guiding your patients through the below instructions and guidelines will help them feel more confident and informed when making the transition to mixed feeding.

Before trying to mix feed an infant The National Health and Medical Research Council (NHMRC) in Australia recommends exclusively breastfeeding until an infant is around 6 months of age,^3,5 to establish a stable milk supply and a strong latch. If this isn’t possible, parents should seek personalised guidance based on theirs and their infant’s needs and circumstances. Infant formula may be given as an alternative to breast milk until 12 months of age.⁵ Formula must be correctly prepared and stored at all times, following the packaging instructions carefully and using the correct scoop without over- or underfilling it.⁵

While breastfeeding is recommended for the first 6-12 months or longer, any amount of breastfeeding provides benefits to both parent and child.⁵ When infant formula is introduced, it’s still ideal for parents to continue to breastfeed in whatever capacity possible (mixed feeding).⁵

When to begin mixing breast milk and formula

To prevent breast refusal and nipple confusion, try gradually introducing formula when beginning mixed feeding.¹ The proportion of formula to breastmilk can be slowly increased as needed once the infant becomes more comfortable with bottle feeding.¹ Note that how much formula an infant will take is unique to the child.

While a parent is mixed feeding their baby

If mixed feeding leads to breast refusal, the breastfeeding parent may experience overfilled breasts – which can be painful or lead to reduced breast milk production.¹ If parents are concerned about milk supply, this indicates they should consider increasing breastfeeding again – even if formula is still offered in a smaller capacity.

It’s important to make bottle feeding a comfortable experience for both parent and infant. Download our safe bottle preparation resource to share with your patients here.

How to use mixed feeding to return to exclusively breastfeeding

Parents should monitor their child’s response to formula and watch for any signs of intolerance. If the infant shows any distress or adverse reaction, they should seek support from a healthcare professional and reduce mixed feeding. If parents are concerned about their decreasing milk production or want to increase the amount they’re breastfeeding, they can:

– Breastfeed more regularly. This is the simplest way to naturally increase milk supply.²⁴

– Express milk after breastfeeding to further increase milk supply.²⁴

– Breastfeed from both breasts first, before offering top-up formula if using.²⁴

– Slowly reduce the amount of formula given in each bottle and gradually decrease the number of formula feeds.

– Use paced bottle feeding to avoid over-feeding formula to their child.²⁴ When beginning mixed feeding, some parents choose to combine formula and breast milk in a single feed.²⁵ However, to prevent wasting breast milk if a bottle isn’t finished, it’s best to offer them separately.²⁵ If parents do choose to combine the two, they must always prepare formula in a separate container, closely following the packaging instructions.²⁵ Breast milk can then be added to the prepared formula if desired.

It takes time for parents to find the right balance between formula and breast milk for them and their baby.

Parents should expect to see changes in the colour, consistency, smell and frequency of their infant’s stools in the process, and will likely notice more gas as their baby adapts to a new food source.²⁶ It can be an adjustment for an infant to get accustomed to a new bottle and teat too, so patience and persistence is key – using a gentle, gradual approach.²⁶

Responding to the infant’s cues quickly when they’re hungry and full is important when breast- and bottle-feeding, as this helps the child feel safe, supported and in-control. Access our responsive feeding guide to share with patients here.

Once parents have started mixed feeding,

they will slowly figure out the ideal balance for them and their baby. Encourage them to consult you or another healthcare professional if they have concerns or questions while transitioning to mixed feeding.

Selecting an infant formula while mixed feeding

Infant formula is the only safe alternative to breast milk for babies under 12 months of age.²⁷ Choosing the most suitable infant formula is essential. As discussed, formulas can be enriched with prebiotic oligosaccharides like scGOS/lcFOS (9:1) which are designed to mimic the amount, diversity and functionality of HMOs in breast milk with benefits on gut flora, digestion and immune health.¹⁵ These formulas can support an infant’s immune system development and function, improving their health outcomes in both the short and long-term.⁸ One or two short-chain synthetic human-identical molecular oligosaccharides (HiMOs) at 1/10th of the dose found in breast milk, is unlikely to mimic the functionality of the total pool of HMOs found in breast milk.²⁶ However, if you have scGOS/lcFOS (short-chain galacto-oligosaccharides and long-chain fructo-oligosaccharides), together with 1 or 2 HiMOs, this brings the pool closer to breast milk in terms of quantity, diversity and functionality,²⁶ allowing formula to more closely mimic breast milk’s functional immune-supporting benefits.²⁸

Other things to consider:

– Standard infant formulas are designed to meet the general nutritional requirements of formula-fed infants.²⁸ They usually contain protein, fats, carbohydrates, vitamins and minerals. In Australia, all standard cow’s milk-based formulas are regulated to ensure they meet strict standards and supply all the essential nutrients needed to support an infant’s normal growth and development.²⁸ – Hypoallergenic formulas are intended for infants with allergies or intolerances to cow’s milk protein. They contain proteins which have been extensively hydrolysed (broken down) to prevent allergic reactions. These may be appropriate for infants with diagnosed allergies to casein and/or whey proteins.²⁹

– Hydrolysed baby formulas are cow’s milk-based, containing protein which has been partially or extensively hydrolysed to make them easier to digest. These may be used for infants experiencing mild digestive discomfort.²⁸

– Anti-reflux formulas are designed to help prevent reflux in infants. They’re a thicker consistency, helping the formula stay down in the infant’s stomach to prevent vomiting and regurgitation. These are generally only used for infants experiencing significant reflux problems.²⁹ – For most infants under 12 months old, cow’s milk-based formulas are generally recommended. Goat’s milk formulas which meet the Australian New Zealand Food Standards Code are also available.⁵

Look out for the following signals an infant may require a change in formula:³⁰

• Allergic reactions
• Colic
• Digestive issues or discomfort (including diarrhoea or constipation)
• Ongoing fussiness or crying
• Excessive gas or bloating
• Skin reactions, including rashes or eczema
• Poor weight gain
• Frequent vomiting or reflux
• Blood in their stools.³⁰

Parental guilt

Some parents feel immense guilt if they’re unable to breastfeed their child in a way they consider “normal” or optimal. If they’d had expectations of breastfeeding being easy, seamless or an opportunity to bond with their child, accepting that this isn’t always possible can be challenging.

Reassure your patients that any amount of breastfeeding they can achieve is beneficial for their baby (and themselves). If breastfeeding is proving impossible, is too difficult or stressful, or is interfering with their lifestyle or mental health, introducing mixed feeding is a way to maintain many of the natural benefits of breastfeeding while easing the burden on them.

Education and resources to provide for parents Support your patients by downloading or sharing these additional information and resources with them.

You’ll find educational resources and guides about breastfeeding, the safe preparation of formula and bottles, introducing solids, newborn FAQs, infant allergy symptoms and prevention, practical tips for the first 1,000 days of an infant’s life and more.

If you want support to determine the most appropriate infant formula for your patients or you’re interested in learning more about Nutricia’s range of evidence-based formulas and products, our Careline team is available to help. The team of expert healthcare professionals, including dietitians, nutritionists and midwives, provide personalised guidance, advice and product support to clinicians and patients. Get in touch via LiveChat or call 1800 438 500 from Mon-Fri 7.30am-5pm (AEST). Your patients can also contact Careline for additional support between their healthcare appointments when needed. Share Careline’s contact details or direct them to the website for further information.

This information is general only and healthcare professionals should rely on their own skill and assessment of patients.

References:

1 – Pregnancy, Birth and Baby. Mixed feeding [Internet]. Canberra: Healthdirect Australia; [cited 2025 May 01]. Available from: https://www.pregnancybirthbaby.org.au/mixed-feeding

2 – Raising Children Network. Mixed feeding: breastfeeding and formula [Internet]. Melbourne: Raising Children Network; [cited 2025 May 02]. Available from: https://raisingchildren.net.au/newborns/breastfeeding-bottle-feeding/bottle-feeding/mixed-feeding

3 – World Health Organization. Breastfeeding [Internet]. Geneva: WHO; [cited 2025 May 01]. Available from: https://www.who.int/health-topics/breastfeeding#tab=tab_1

4 – Western Sydney Local Health District. Mixed feeding your baby [Internet]. Sydney: WSLHD; 2021 Aug [cited 2025 Apr 28]. Available from: https://www.wslhd.health.nsw.gov.au/ArticleDocuments/2243/Mixed%20feeding%20V4.pdf.aspx

5 – National Health and Medical Research Council. Infant feeding guidelines [Internet]. Canberra: NHMRC; 2012 [cited 2025 May 02]. Available from: https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n56_infant_feeding_guidelines.pdf

6 – McAndrew F, et al. Infant feeding practices and the role of mixed feedin

g in early infancy. Matern Child Nutr. 2024;20(1):e13610.

7 – University of Glasgow. Infants in industrialised nations are losing a species of gut bacteria that digests breast milk [Internet]. Glasgow: University of Glasgow; 2023 Apr [cited 2025 May 01]. Available from: https://www.gla.ac.uk/news/archiveofnews/2023/april/headline_933082_en.html

8 – Bode L, et al. Human milk oligosaccharides and infant gut microbiota: a review. Front Nutr. 2023;10:1194679.

9 – Newburg DS, Neubauer SH. Human milk composition. In: Jensen RG, editor. Human lactation. San Diego: Academic Press; 1995:273–349.

10 – Geneva Infant Feeding Association. Breastmilk composition [Internet]. Geneva: GIFA; [cited 2025 May 03]. Available from: https://www.gifa.org/en/breastmilk-composition/

11 – Danone Research. The orchestral composition of human milk [Internet]. Australia: Danone Research; [cited 2025 May 01]. Available from: https://www.danoneresearch.com/human-milk-research/the-orchestral-composition-of-human-milk/

12 – Bruzzese E, et al. Intestinal microflora composition in infants with colic: a prospective case-control study. Clin Nutr. 2009;28:156–61.

13 – National Health and Medical Research Council. Infant feeding guidelines: summary [Internet]. Canberra: NHMRC; 2013 [cited 2025 May 02]. Available from: https://www.eatforhealth.gov.au/sites/default/files/files/the_guidelines/n56_infant_feeding_guidelines_summary_150916.pdf

14 – Fan W, et al. Human milk oligosaccharides and infant gut microbiota. Sci Rep. 2019;9:38268.

15 – Salminen S, et al. Probiotics and prebiotics: health benefits and safety. Nutrients. 2020;12(7):1952.

16 – Saturio S, et al. Effects of probiotics on gut microbiota in infants. Microorg. 2021;9(12):2415.

17 – Singh R, et al. Infant formula and gut microbiota: a review. Food Res Int. 2022;151:110884.

18 – Moro G, et al. Clinical effects of prebiotics in formula-fed infants. J Pediatr Gastroenterol Nutr. 2002;34:291–5.

19 – Knol J, et al. Colon microflora in infants fed formula with prebiotics. J Pediatr Gastroenterol Nutr. 2005;40:36–42.

20 – Stanford Medicine. Infant gut microbiome and breast milk [Internet]. Stanford: Stanford University; 2022 Jun 10 [cited 2024 Oct 1]. Available from: https://med.stanford.edu/news/all-news/2022/06/infant-gut-microbiome-breast-milk.html

21 – van den Elsen LWJ, et al. The role of human milk oligosaccharides in immune development. Front Pediatr. 2019;7:47.

22 – Jeurink PV, et al. Human milk oligosaccharides in infant nutrition and health. Benef Microbes. 2013;4(1):17–30.

23 – Ojima M, et al. Infant gut microbiota and breastfeeding. ISME J. 2022;29:1–5.

24 – The Royal Women’s Hospital. Low milk supply [Internet]. Melbourne: The Women’s; [cited 2025 May 26]. Available from: https://www.thewomens.org.au/health-information/breastfeeding/breastfeeding-problems/low-milk-supply

25 – World Health Organization. Safe preparation, storage and handling of powdered infant formula [Internet]. Geneva: WHO; 2007 [cited 2025 May 26]. Available from: https://www.who.int/publications/i/item/9789241595414

26 – Children’s Health Queensland. Responsive breast and bottle feeding [Internet]. Brisbane: Queensland Health; 2021 Dec 17 [cited 2025 May 26]. Available from: https://www.childrens.health.qld.gov.au/resources/our-work/ellen-barron-family-centre/responsive-breast-and-bottle-feeding

27 – NSW Government. Feeding your baby [Internet]. Sydney: NSW Government; [cited 2025 May 26]. Available from: https://www.nsw.gov.au/family-and-relationships/having-children/having-a-baby/after-your-baby-born/feeding-your-baby

28 – Wiciński M, Sawicka E, Gębalski J, et al. Human milk oligosaccharides: health benefits, potential applications in infant formulas, and pharmacology. Nutrients. 2020 Jan 20;12(1):266.

29 – NHS. Types of formula milk [Internet]. London: NHS; [cited 2025 May 26]. Available from: https://www.nhs.uk/conditions/baby/breastfeeding-and-bottle-feeding/bottle-feeding/types-of-formula/

30 – Pregnancy, Birth and Baby. Milk intolerance in babies and children [Internet]. Canberra: Healthdirect Australia; [cited 2025 May 26]. Available from: https://www.pregnancybirthbaby.org.au/milk-intolerance-in-babies-and-children