Why breast milk is treated like medicine for a preterm baby

For a baby born early, your breast milk is more than food. It protects a fragile gut, lowers the risk of a serious bowel disease called NEC, and helps fight infection. That is why NICU teams ask for every drop, and why donor milk is the next best choice when a mother's own milk is not yet enough.

Why is breast milk so important for a premature baby?

Breast milk protects a premature baby's immature gut in ways formula cannot. WHO strongly recommends a mother's own milk for feeding preterm and low birth weight babies, including the smallest ones.¹

Human milk carries antibodies, living white cells and special sugars that feed helpful gut bacteria. When trials compared formula with donor breast milk in preterm babies, formula nearly doubled the risk of NEC (necrotising enterocolitis).² Your own fresh milk is better still, because it is made for your baby and has not been heated.

What is NEC and why do doctors worry about it?

NEC (necrotising enterocolitis) is a serious illness in which part of the bowel wall becomes inflamed and starts to die. It mostly affects babies born well before term, often in the second or third week as feeds increase.

Signs include a swollen tummy, green or bloody vomit, blood in the stool and a baby who suddenly looks unwell. Some babies recover with rest of the gut and antibiotics. Others need an operation. Formula feeding raises the risk, which is why we push so hard for human milk.²

When should I start expressing milk after a premature birth?

Start as soon as you can, ideally within the first hour after birth. Early starting helps your supply for weeks to come.

In a small trial, mothers of very low birth weight babies who started expressing within one hour made more milk in the first week and at three weeks, and their milk "came in" sooner than mothers who started 1 to 6 hours after birth.³ After a caesarean, ask the nurse to help you hand express while you are still in bed. Even a few drops of colostrum (the thick first milk) are worth collecting in a syringe.

How can I make more breast milk when my baby is in the NICU?

Express often, day and night, and use your hands as well as the pump. A pump is not a baby, so you need to give your body more signals.

• Express at least as often as a baby would feed, including once in the night.
• In the first days, hand express colostrum. In one study, mothers who hand expressed more than 5 times a day in the first 3 days were making more milk at 8 weeks than the group as a whole.⁴
• Massage the breast while pumping. Mothers taught this "hands-on pumping" raised their daily milk volume by about half.⁴
• Express near your baby, or straight after skin to skin care.

In joint families, this is where others can help most: cooking, washing pump parts and bringing milk to the NICU.

What is colostrum mouth care?

Colostrum mouth care means placing tiny drops of your first milk inside your baby's cheek, even before milk feeds by tube begin. It is gentle and safe.

A Cochrane review of six small trials did not find clear proof that it reduces NEC, infection or death.⁵ The trials were too small to be sure either way. Dr Dutta still likes it, because it gets your milk to your baby on day one and helps you feel part of the care.

What is donor breast milk and is it safe?

Donor milk is breast milk given by other healthy mothers, screened and pasteurised (heat treated) by a human milk bank. When your own milk is not enough, it is the next best option.

The American Academy of Pediatrics says pasteurised donor milk is safe when donors are screened and the milk is collected, stored and heat treated by an established milk bank. It advises against informal milk sharing from friends or online.⁶ WHO says donor milk may be considered for preterm babies when a mother's own milk is not available.¹ Some families worry about another woman's milk. Dr Dutta thinks of it as a bridge. As your supply grows, your milk takes over.

Is formula harmful for a premature baby?

Formula is not poison, and many babies have grown well on it. But for very premature babies, human milk is safer for the gut.

Babies fed formula grew a little faster in hospital, but had more NEC: about one extra case for every 33 babies fed formula instead of donor milk.² WHO suggests special preterm formula for very small babies only when neither mother's milk nor donor milk is available.¹

Why does my baby need fortifier in breast milk?

Breast milk alone does not have enough protein, calcium and phosphate for a very small baby's fast growth. Fortifier is a powder or liquid added to expressed milk to fill that gap.

A Cochrane review found that fortified breast milk led to modestly faster gains in weight, length and head size in hospital.⁷ WHO says fortifier should not be given to every preterm baby, but may be considered for babies born before 32 weeks or weighing less than 1.5 kg.¹ Fortifier does not spoil your milk. It adds what is missing and keeps everything that protects.

How fast are milk feeds increased in the NICU?

Feeds start small and go up step by step. Most units now increase feeds steadily rather than very slowly.

The UK SIFT trial, published in the New England Journal of Medicine in 2019, compared daily increases of 30 mL per kg with 18 mL per kg in 2804 very preterm or very low birth weight babies. Survival without disability at two years, infection and NEC were similar in both groups.⁸ WHO now allows daily feed increases of as much as 30 mL for each kg of body weight.¹ While feeds build up, a drip gives sugar, protein and fat straight into a vein.

What are probiotics and why is my baby getting them?

Probiotics are drops of helpful bacteria. In very preterm babies they probably lower the risk of NEC and death.

A Cochrane review of 60 trials found probiotics roughly halved NEC in babies born before 32 weeks or under 1.5 kg. About one case of NEC was prevented for every 33 babies treated.⁹ The evidence was weaker in the very smallest babies, where little benefit was seen.⁹ WHO says probiotics may be considered for very preterm babies fed human milk.¹ Products differ in quality, so each unit chooses its own.

Does my premature baby need vitamins and iron?

Usually yes. Preterm babies miss the iron and vitamin stores built up in the last weeks of pregnancy.

WHO strongly recommends iron supplements for preterm or low birth weight babies fed breast milk who are not getting iron from another source. It also says vitamin D may be considered.¹ The American Academy of Pediatrics advises at least 400 IU of vitamin D a day for all infants, starting soon after birth.¹⁰ Your doctor will tell you the dose and when to start.

When can my premature baby start breastfeeding directly?

As soon as your baby is able. WHO advises putting babies to the breast as soon as possible, and giving expressed milk by tube or cup until then.¹

Early attempts are short. Your baby may lick and nuzzle before sucking well. Skin to skin care is the best practice ground. Over days to weeks, tube feeds are reduced as breastfeeds or cup (paladai) feeds take over. Expect ups and downs, because a baby who fed well yesterday may be tired today.

What will the nurse watch for while feeds are going up?

The nurse watches your baby's tummy, stools, vomiting and general behaviour at every feed. Small changes can be early signs of trouble.

She may feel the tummy, measure its size, and check what comes back up the feeding tube. Babies on full feeds also get regular weight checks, and growth is plotted on a chart. If anything looks wrong, feeds may be paused while the doctor checks. A short pause is common and usually just a precaution.

When should I tell the nurse something is wrong?

Tell the nurse or doctor straight away if you notice any of these, because they can be early signs of NEC or infection.

• A tummy that looks swollen, tight, shiny or discoloured.
• Green, yellow or bloody vomit.
• Blood in the stool.
• More milk than usual coming back up the tube.
• Your baby suddenly becomes pale, floppy, very sleepy or has more breathing pauses.