Breastfeeding the Sick Baby Part 2

When a baby is ill, either with an acute or a chronic illness, it is important to make every effort to ensure that the mother continue breastfeeding him. In fact, it is not only possible, but good for both the baby and the mother to continue breastfeeding.  Sick babies need to continue breastfeeding, especially if the illness is due to an infection since the immune factors in breastmilk continue to be produced and even adapt to the bacteria or viruses which are making the baby ill.  Since mothers and babies, being in such close physical contact, share bacteria and viruses, the mother will likely produce antibodies to the very infection that is causing the baby to be ill.  Furthermore, the baby is comforted by breastfeeding, especially when he is sick. Mothers need to continue breastfeeding to prevent breast engorgement. Most importantly, not only does breastfeeding comfort the baby but also at the same time, the mother is comforted by breastfeeding the baby. 

Help with breastfeeding

Are there some illnesses in the baby that absolutely require mothers to avoid breastfeeding?

There are very rare instances when a baby’s illness requires interruption of breastfeeding or the baby not receiving breastmilk.  Galactosemia, caused by an inborn error of metabolism where the baby is unable to metabolize the sugar galactose properly is one such illness. Galactose is one of the two sugars making up lactose, the sugar present in breastmilk.  The other is glucose.

Because the baby cannot metabolise the galactose in the usual way, an alternate pathway of metabolism is taken which results in a toxic compound, galactitol, being formed. This toxic compound results in the baby developing liver disease, cataracts of the eye, brain injury and if removal of galactose from the baby’s diet is not instituted, the baby will eventually die.

There is no way to remove galactose from breastmilk, at least at present, so a baby who has the full syndrome of galactosemia must not be breastfed.  However, some babies have only “partial” galactosemia (Duarte variant) where they have some enzyme to metabolize galactose (as much as 10-25% of normal levels).  These levels of enzyme result in the baby’s being able to metabolize galactose adequately without suffering the devastating effects seen in classic galactosemia. They can and should breastfeed, just as any other baby. Babies with lower levels of enzyme can be partially breastfed. Incidentally, partial galactosemia is far more common than the full disease.

Other inborn errors of metabolism may also make breastfeeding more hazardous than artificial feeding.  Tyrosinemia is, perhaps, one of them, but it is so rare that whether breastfeeding is possible for the baby has not been properly studied. The treatment of tyrosinemia is a “low protein diet”, but breastmilk has significantly less protein than most formulas. Furthermore, since most of the protein in breastmilk is not absorbed from the intestinal tract, so it may be possible for a baby with tyrosinemia to be at least partially breastfed. (Lactoferrin and antibodies combined make up 60 to 70% of all the protein in breastmilk and are not absorbed by the baby).

As for maple syrup urine disease and many other extremely rare inborn errors of metabolism, we just don’t know. The “default” treatments are usually special formulas, even though it may be possible for the babies to breastfeed. The idea in the minds of too many specialists is that since “formula is just like breastmilk” and ordinary formula is contraindicated in these rare diseases, therefore breastmilk and, obviously, breastfeeding are also thought to be contraindicated.  Maybe they are, but assuming they are without proof, is just not good practice. Just as in the case of how much less protein is absorbed from the baby’s gut, perhaps other differences between breastmilk and formula would make it possible for the baby to breastfeed safely.

Phenylketonuria (PKU)

Babies with phenylketonuria can breastfeed, at least partially. Here is how, once upon a time, we got babies with PKU to breastfeed at the Hospital for Sick Children in Toronto.  “Once upon a time”, because I understand that now, the mothers with babies with PKU are just simply told they can’t breastfeed at all.  I think that is a pity because they could breastfeed, and the babies would have not only breastmilk, but they would have that special relationship of breastfeeding.  It is too bad however, that this notion of a close, physical and emotional relationship that is breastfeeding does not fit the “medical model”.

The issue is that babies with PKU cannot metabolize phenylalanine to tyrosine, and the buildup of phenylalanine results in brain damage and cataracts amongst other things.  However, phenylalanine is an essential amino acid, meaning that you need it for proper metabolism.  So, the baby with PKU needs phenylalanine, but not too much.

Back in the 1980s when I had just started the breastfeeding clinic at the Hospital for Sick Children, the people from the phenylalanine clinic came to me and asked how they could help mothers breastfeed longer.  The babies were stopping breastfeeding very soon after birth, usually by the time the baby was 2 or 3 weeks old.  And it’s easy to see why.

Before my suggestion on how to help the mothers breastfeed, the mothers were told to feed in this way:

  1. The baby would be weighed before the feeding.
  2. The mother would then feed the baby 10 minutes on each side (by the clock).
  3. The mother would weigh the baby after the feeding at the breast.
  4. The mother would give the rest of the feeding (calculated by the dietician to make sure the baby didn’t get too much phenylalanine) as low phenylalanine formula.

One needs only a smidgen of breastfeeding knowledge to know why this would not work.

  1. The mother had to carry the scale with her wherever she went.
  2. One can easily imagine that the mother would be anxious about the baby getting “too much breastmilk” and thus causing the baby to get too much phenylalanine resulting, likely, in the mother restricting the baby’s time on the breast.
  3. The babies started to prefer the bottle, which is not surprising.

I came up with this solution

  1. The dietitian would calculate the approximate quantity of low phenylalanine formula the baby would require.
  2. The mother would give this amount of low phenylalanine formula at the beginning of the feeding at the breast with a lactation aid at the breast.
  3. Then, allow the baby to finish the feeding on the breast.
  4. The amount of low phenylalanine formula would be adjusted depending on the blood levels that were normally followed anyway.

We learned that the low phenylalanine formula was thicker than usual formulas, so it did not pass easily through the usual 5F tube we used for supplementing at the breast.  So, we used a larger 8F tube which has a wider bore through which the milk will pass.  And it worked well.

What happened? During the first year, breastfeeding continued much longer.

  1. One baby breastfed to 18 months of age
  2. Several breastfed to 6 months
  3. One baby who had atypical PKU was able to be breastfed exclusively for six months

Premature babies and babies with congenital heart disease and other illnesses

It is uncommon for premature babies in North America to leave hospital breastfeeding exclusively. One reason is that few special care units practice true Kangaroo Mother Care.  Mothers are often told that premature babies cannot breastfeed until they are 34 weeks gestation, which is incorrect.  Experience from Scandinavia shows that some premature babies can start going to the breast by 27 weeks gestation.

Furthermore, the lack of confidence that many neonatologists have in breastmilk and breastfeeding results in too many babies getting “fortifiers” mixed in with breastmilk (the quotation marks are to suggest that when “fortifiers” are used unnecessarily, as they often are, they should be called breastmilk “weakeners”). “Fortifiers” are mixed with expressed breastmilk to increase nutrients that are felt to be missing or in inadequate amounts in breastmilk alone.  The use of “fortifiers” may sometimes be necessary, but not routinely, as is usual in many special care units.

A baby born at 28 weeks, breastfeeding and latched on at 2 weeks of age.

This baby is 2 weeks old. He was born at 28 weeks gestation. He is latched on and drinking from the breast

Premature babies can breastfeed

Triplets born prematurely, managed to get out of the NICU without every getting bottles or having “fortifier” added to the breastmilk.











Babies with congenital heart malformations, cardiomyopathy and other heart problems.

Is it important for these babies to breastfeed?  Of course! Is it important for these babies to breastfeed?  Babies with heart diseases need comfort and security just like all babies.   And they need the immunity provided by breastfeeding because they are often in hospital for long periods of time and we know that hospitals are not the best places to avoid infections.  Infection in a baby with congenital heart disease can be fatal.

These babies are often fed by bottles because it is thought, wrongly, that breastfeeding is too tiring for a baby with heart disease.  This also is simply not true.  Breastfeeding is not tiring for the baby.

The idea that breastfeeding is tiring for the baby arises from the false belief that “babies transfer milk”, in other words that babies “suck milk out of the breast”. But this is not not understanding breastfeeding and how breastfeeding works.  Babies do not “suck milk out of the breast”.  Babies stimulate milk to be released from the breast, and the mother “transfers” the milk to the baby.

The other issue that arises with babies with congenital heart malformations is that some of them have heart failure.  Thus, cardiologists limit the amount of liquid (including breastmilk) that the baby can receive.  I would think that careful physical examination and close monitoring of these babies will allow the babies to breastfeed without limiting the frequency or the length of time the baby is at the breast.

If it becomes truly necessary to limit the amount of breastmilk the baby receives, it is reasonable, given the importance of breastfeeding (breastfeeding is more than the milk) to increase the diuretics (“water pills”) and other medications that stimulate the heart to work more efficiently or decrease the work of the heart.  True, higher doses of medication may cause more side effects, but I believe strongly that breastfeeding is worth the risk.

It is also possible to keep intravenous fluids to a minimum.

And if it is truly necessary to limit the amount of breastmilk a baby gets.  The mother can express her milk just before a feeding and give back the baby the “required” amount of milk with the lactation aid at the “dry” breast.


A special situation arises when a baby develops a chylothorax.  This problem usually arises after cardiac surgery, but an occasional baby is born with it for no obvious reason.  In the case of chylothorax after heart surgery, the thoracic duct, which brings lymph back to the heart to be returned to the blood is unavoidably nicked.  This results with lymph accumulating in the space between the lung and the chest wall.

A chylothorax is usually treated with a low-fat diet and chest drainage.  The reason for the low-fat diet is that it decreases the lymph flow in the thoracic duct.  This treatment is fine for an adult who can manage for a while on a low-fat diet, but not a baby, who needs fat to grow and develop.

The chest drainage is done as it would be for an adult or older child, but usually the cardiologists insist that the baby must not breastfeed but must drink a formula with medium chain triglycerides.  Why medium chain triglycerides?  Interestingly they do not get absorbed into the lymph, but rather are absorbed directly into the blood, so do not increase lymph flow.

But something can be done.  Instead of special formula, the mother’s breastmilk can be used instead.  The milk is centrifuged, and the fat which is at the top of the centrifuged milk is taken off and stored for later use.  The people in the nutrition department then add medium chained triglycerides to the milk.  It’s not quite breastmilk but it’s better than the formula.

Just before feeding the baby, the mother pumps out as much milk as practical, and feeds the baby with a lactation aid at the breast on the “dry breast” (recently pumped breast).  The baby will probably still get some breastmilk from the breast, but the formula with medium chain triglycerides is not completely free of long and short chain triglycerides either.  Using the lactation aid on the “dry” breast will prevent the problem of the baby refusing to latch on to the breast after several weeks, which the treatment of chylothorax may require.

The baby with cystic fibrosis

Is it important for these babies to breastfeed?  Of course! Babies with cystic fibrosis need comfort and security too.  And they need the immunity provided by breastfeeding because they are often in hospital for long periods of time and we know that hospitals are not the best places to avoid infections.  Infection in a baby with cystic fibrosis can be fatal since they very easily develop infections of the lungs.

Most babies with cystic fibrosis have difficulty digesting their food, probably also including breastmilk.  But breastmilk does contain lipase (the enzyme that digests fat), proteases (the enzymes that digest protein) and amylase (which breaks down complex carbohydrate). It is likely that unless the baby has a relatively mild form of pancreatic enzyme insufficiency, the baby will still need extra enzymes, but maybe smaller amounts.

The enzymes can be given to the baby by an open glass cup.

It is impossible to discuss every possible illness a baby/toddler may have, but with an understanding (health worker’s and mother’s) of how breastfeeding works, with a commitment to breastfeeding, with good support, good hands on help, and with some imagination, breastfeeding, and not just “breastmilk”, can not only be salvaged but actually made to work very well despite many types of illness too frequent and varied to discuss here.  These examples can give an approach which may work for other illnesses that babies/toddlers may be born with or develop.

Why bother with all this?

Because breastmilk and breastfeeding are important to the physical and emotional health of the baby as well as of the mother’s.  Especially the baby who is sick, who needs the physical and emotional contact of breastfeeding even more than a healthy baby, who also needs it.  And the mother needs breastfeeding also because she gets the physical and emotional contact of breastfeeding.  And she will feel that she is contributing to the treatment of her baby.  And she is right.  Too bad that only a few pediatricians/neonatologists understand this.

Need breastfeeding help? Make an appointment with the International Breastfeeding Centre.

Copyright: Jack Newman, MD, FRCPC, Andrea Polokova, 2017, 2018, 2021