Feeding your premature baby breast milk

It’s especially important for a premature baby to have breast milk, but breastfeeding directly can be challenging. Read our expert’s advice to help you give your preemie all the benefits of your milk

If your baby is born before week 37 of your pregnancy, they’ll be classed as premature.¹ We don’t always know what causes premature birth, but there are factors that increase the likelihood. These include a twin or multiple pregnancy, certain health conditions affecting the mum or foetus, or having had a premature baby previously.

Because premature babies have had less time in the womb, they have some extra growing to do, and may be more vulnerable to illnesses and infections. They may also need to spend time in a neonatal intensive care unit (NICU).

Why is breast milk so important for a premature baby?

Breast milk is important for the optimal growth and development of full-term infants, and it’s even more important for premature babies.

Important factors, such as DHA (a fatty acid vital for healthy brain and eye development)and immunoglobulin G (an antibody), are transported from mum to foetus via the placenta throughout pregnancy.^2,3 Because they arrive early, premature babies have not fully received these important factors in the womb, but milk from mums of premature infants contains more fats and secretory immunoglobulin than milk from mums of full-term babies.⁴

Premature babies also have immature gastrointestinal tracts, which can cause difficulties with digestion and absorption of nutrients, so they need a food that’s easy for their delicate guts to process. Your breast milk contains enzymes that help your baby with digestion,⁵ as well as epidermal growth factor, which in turn helps their intestine mature.⁶ Premature babies fed mainly on breast milk have significantly lower intestinal permeability than those predominantly given formula, which means that fewer (potentially disease-causing) particles can pass through the lining of their intestines into their bloodstream.⁷

Breast milk is so important for preemies that if their own mums can’t, for whatever reason, provide them with enough milk at first, they may be fed donor milk from other breastfeeding mums to bridge the gap, rather than formula. 

Does breast milk give preemies better outcomes?

Your breast milk includes protective agents that can help prevent serious conditions your preemie is susceptible to,⁸ such as severe infections,⁹ retinopathy of prematurity (which can cause loss of vision)¹⁰, and bronchopulmonary dysplasia (a chronic lung disease).¹¹

The more breast milk your baby has, the lower their risk of disease.¹² Each additional 10 ml (0.3 fl oz) a day, per kg (2.2 lb) of a baby’s weight, reduces the risk of sepsis by 19%.9And the risk of necrotising enterocolitis (NEC), a potentially fatal bowel condition, is also up to ten times lower in preemies who have breast milk compared to those who are formula-fed.¹³ So every drop counts!

Most importantly, premature infants fed with their mum’s milk tend to be discharged two weeks earlier on average than those who are formula-fed.¹⁴ They’re also almost 6% less likely to be readmitted to hospital in the first year.¹⁵

In the longer term, breast milk is also proven to improve mental and physical development – research shows that low-birthweight infants who were given breast milk in intensive care have as much as a five-IQ-point advantage over those who weren’t¹⁵ – as well as having better cardiac function in later life.¹⁷

Will I have milk if my baby is unexpectedly early?

Yes – mums are ready to produce breast milk in mid pregnancy. When the placenta is delivered after your baby’s birth, your levels of the pregnancy hormone progesterone drop, allowing your breasts to start producing colostrum, your early milk. Usually a mum’s milk supply will be triggered by her newborn baby latching on to her breast and suckling rhythmically, but if your baby comes early, they may not be able to breastfeed at first.

You can reproduce the sensations that trigger supply by stimulating your breasts and nipples with your hands, or by using a breast pump, which could help you collect that nutrient-rich colostrum to give to your baby¹⁸ – see below for more on what to do if your preemie can’t breastfeed yet.

A mother’s milk usually ‘comes in’ around two to four days after the birth but if you’ve delivered prematurely this can sometimes be delayed. However, a recent study showed that mothers who pumped within one hour of delivery had their milk come in at the expected time.¹⁹ That’s also why it’s important to start expressing breast milk as early as possible.

How can I prepare if I know my baby will be premature?

Visit the neonatal intensive care unit (NICU) to see what it looks like and how staff take care of premature babies. It’s also a good idea to find out how breast milk is produced and expressed, and understand its importance not only for nutrition, but also as a medicine for these babies – read more in Medela’s free ebook The Amazing Science of Mother’s Milk.

What if my preemie can’t feed from the breast?

Many babies born before 34 weeks struggle to coordinate their sucking, swallowing and breathing. Until your baby is ready, nurses will gently place a tube into their tummy through their nose or mouth to feed them. All your baby’s feeds can be given this way until they are ready to start feeding from your breast.

If your baby is too weak to stay latched on to your breast and feed, you can use your hospital or birth facility’s breast pump to ‘be the baby’. Stimulating your breasts with research-based initiation technology²⁰ – which mimics the sucking patterns of human infants – in the first hours²¹ is important to help initiate and maintain your milk supply.

You’ll need to express milk as often as a healthy newborn would normally feed. This means pumping every two to three hours – in other words, a minimum of eight to 12 times over 24 hours.

Some mums may be able to administer small amounts of expressed breast milk into their baby’s mouth with a syringe. Or you can put cotton buds soaked with breast milk inside your baby’s mouth.²² This allows your baby to taste your milk – which can make it easier to move on to full breastfeeding – and coats their mouth with your milk’s immune-boosting, protective components. There are many ways to be involved, so ask your healthcare professionals what you can do for your baby. 

Very low birthweight babies, under about 1.5 kg (3 lb 5 oz), often need extra protein, calcium and phosphorous­, so a fortifier is given to them along with mother’s milk. In some countries, human-derived milk fortifiers are available, but here in Japan they’re derived from cow’s milk.

Do you have any tips for expressing milk?

If your baby is expected to stay in the NICU for a while, neonatologists recommend using a double breast pump to express milk for him – I always recommend the Medela Symphony. Double pumping doesn’t just enable you to express more quickly, it also delivers 18% more milk on average than pumping from one breast at a time.²³

I also encourage mums to find the most comfortable situation they can for expressing. It’s widely recognised that the best time to pump is immediately after or during prolonged skin-to-skin contact with your baby (see below for more on this ‘kangaroo care’), or while you’re at their bedside and can look at them while you express. Oxytocin, the hormone that induces your let-down reflex, is released by watching, touching, smelling and thinking of your baby,²⁴ so NICU staff should offer a comfortable place and relaxed atmosphere where you can do this.

What is kangaroo care for premature babies?

Kangaroo care is when parents keep their newborn skin-to-skin against their bare chests for extended periods, and it can have many incredible benefits for you, your baby and your milk supply. Skin-to-skin contact helps calm and regulate your baby’s breathing and heartbeat, as well as keeping them warm and letting them rest close to you or your partner. Kangaroo care is also associated with better health in premature babies.²⁵ For mums, it is associated with higher volumes of expressed milk²⁶ and a longer duration of breastfeeding.²⁷ Making time for skin-to-skin at least 30 to 60 minutes before a feed gives your baby time to wake up and feel hungry, rather than rushing them.

What if NICU staff offer formula milk?

Don’t hesitate to let them know you want to give your baby breast milk, not formula. If your breast milk is not enough for your baby, ask NICU staff for more support to increase your milk production.

It is normal for all mums with babies in the NICU to feel worried or stressed. These feelings can sometimes affect milk production, so it’s really important to ask for as much help as you need. Remember, it’s your right to ask for support. Your healthcare professionals can introduce you to the right person to give you breastfeeding help, such as a lactation consultant.

What about milk banks for donor milk?

The American Academy of Pediatrics has stated that if own mother’s milk is unavailable, despite significant support with breastfeeding, pasteurised donor milk should be used.²⁸ Certified milk banks have high standards for screening and testing potential donors, for pasteurisation, and for testing milk prior to being used in hospitals, to minimise the potential for transmitting infections.

How can I move from expressing to direct breastfeeding?

Whatever the gestational age of your baby, if they are stable enough to be held skin-to-skin then you may find they seek your breast for some practice (non-nutritive) sucking. This is the perfect way for them to start learning how to breastfeed before they are ready to fully coordinate sucking, swallowing and breathing.

Babies love the smell of breast milk, so expressing some on to your nipple before putting your baby on the breast may help them find your nipple and make them want to suck. They may even be able to get a little milk when latching on. Don’t worry if they seem to be doing very little – they are learning every time. Eventually they may start having one or two sucks and move to a full breastfeed. Until then, they can be fed milk through a tube while you hold them close to your breast, as this may help your baby to associate having a full tummy with your breast and milk.

Non-nutritive breastfeeding can begin as soon as you feel comfortable with kangaroo care as long as your baby does not have bradycardia (a slow heartbeat) or desaturation (low blood oxygen). Your baby can move to breastfeeds when they are capable. They’ll gradually build strength to sustain a longer latch and take more milk over time.