Slow Weight Gain Following Early Good Weight Gain


Sometimes, babies who were doing very well and gaining weight very well with exclusive breastfeeding start to gain more slowly and even not at all after two to four months. Exclusively breastfed babies do tend to gain more slowly after three or four months compared to artificially (formula) fed babies but this is normal. The more rapid weight gain of the artificially fed baby is not the standard. Breastfeeding is the normal, natural, physiologic way of feeding infants and young children. Using the artificially fed baby as the model of normal is not rational and leads us to make errors in advising mothers about feeding and growth.

In some cases, however, an illness in the baby may result in slower than expected weight gain. Supplementing with formula does not cure the illness and may rob the baby of the beneficial effects of exclusive breastfeeding.

You can tell when a baby is getting milk and when he is not (see below and the video clips at the website If the baby is sucking at the breast and not getting milk, well, this explains why he is not gaining weight and it is most likely the mother’s milk supply is down. The mother’s milk having decreased is the most common reason that the baby fusses and pulls at the breast and/or no longer gains weight well enough.

Why would your milk supply decrease?

  1. You have gone on the birth control pill, the Mirena IUD, have received Depo Provera or are taking estrogens and/or progesterones in another way. It should be noted that breastfeeding itself has a significant contraceptive effect, especially if you are breastfeeding exclusively.
  2. You are pregnant. Pregnancy definitely decreases the milk supply.
  3. You have been trying to stretch out the feedings or “train” the baby to sleep through the night. If this is the case, feed the baby when he is hungry or sucking his hand. Consider safe co-sleeping so the baby feeds at night and you don’t have to get up to feed him.
  4. You are using bottles more than occasionally. It is better to avoid bottles altogether, but the occasional bottle is not usually going to influence your milk supply. However, regular, frequent bottle use results in the baby latching on less well and thus getting milk less well from the breast. Often the baby will pull off before he has “emptied” the breast, and the milk supply decreases. See below under “This reason requires more explanation”. If you must have the baby fed by someone other than you, then a cup (not a sippy cup as that is the same as a bottle) would be better than a bottle. See the video clips at the website
  5. An emotional shock can, occasionally, decrease the milk supply.
  6. Sometimes an illness in the mother, particularly if the illness is associated with fever, can decrease the milk supply. Mastitis and blocked ducts can also decrease milk supply. Fortunately this doesn’t happen most of the time.
  7. Could you be doing too much? It is easy to get caught up in trying to conform to others’ ideas of what you should be doing. Let the housework go. Sleep when your baby sleeps. If you are tired, lie down with the baby to breastfeed and let yourself fall asleep. Make sure co-sleeping is done safely according to theguidelines set out by UNICEF and UK Baby Friendly .
  8. Some drugs may decrease your milk supply. It is possible antihistamines do, especially the older ones such as Benadryl; pseudoephedrine (Sudafed) can also decrease the milk supply. Note that these two drugs (or similar ones) are found in cold and allergy medicines.
  9. You are feeding one side only at each feeding. It is not a good idea to feed the baby on just one side, to follow a rule. Yes, making sure the baby “finishes” the first side before offering the second can help treat poor weight gain or colic in the baby, but rules and breastfeeding do not go together well. If the baby is not drinking, actually getting milk, there is no point in just keeping the baby sucking without getting any milk for long periods of time. You should “finish” one side and if the baby wants more, offer the other.

    How do you know the baby is “finished” the first side? Because the baby is no longer drinking, even with compression (see the video clip and information sheet on compression) This does not mean you must take the baby off the breast as soon as the baby doesn't drink at all for a minute or two (you may get another milk ejection reflex or letdown reflex, so give it a little time), but if it is obvious the baby is not drinking, take the baby off the breast and if the baby wants more, offer the other side. How do you know the baby is drinking or not? See the video clips at the above website.

    If the baby lets go of the breast on his own, does it mean that the baby has “finished” that side? Not necessarily. Babies often let go of the breast when the flow of milk slows, or sometimes when the mother gets a milk ejection reflex and the baby, surprised by the sudden rapid flow, pulls off. Try him again on that side if he wants more, but if the baby is obviously not drinking even with compression, switch sides.

  10. A combination of the above.
  11. Sometimes, the milk supply decreases for no obvious reason.Well, maybe the reason is not so difficult to figure out as that once you consider the information in the following paragraph and know how to know a baby is getting milk from the breast (or not).

    This reason (number 11) requires more explanation.

    In the first few weeks, babies tend to fall asleep at the breast when the flow of milk slows down. This slowing of the flow occurs earlier in the feeding if the baby is not latched on well. A baby who has a less-than-good latch but whose mother has an abundant supply can gain well, but he really depends on the milk ejection (letdown) reflex in order to get milk. The baby will suck and sleep and suck, without getting large quantities once the initial rapid flow diminishes but if the mother has more milk ejection reflexes, he will drink some more, even half asleep. Once the baby is older, however, some may pull away from the breast when the flow slows down, often within minutes of starting the feeding (Actually some do this from very early on, some never do this, and some do a combination of sleeping and pulling away from the breast depending probably on how hungry they are or their mood). This is more likely to occur when babies have received bottles from early on, but can also occur even without the baby’s having received bottles. When this pulling occurs, most mothers will probably put the baby over to the other side but then the same thing happens. The baby may still be hungry and may refuse to take the breast again, preferring to suck his hand. He won’t get those extra milk ejection reflexes (letdown reflexes) that he would have gotten if he had stayed longer at the breast. So, the baby drinks less and the supply also decreases because he drinks less and the flow slows even earlier in the feeding (because there is less milk) and a vicious circle has started. It doesn’t always happen this way and many babies may gain weight well even if they do spend only a short period of time on the breast. They may still pull off the breast and suck their hands because they want more sucking (which is pleasurable for them) but if their weight gain is good, there is no need for concern. Still, it’s nice to have a baby breastfeed without pulling at the breast.

    The way to prevent this all is to get a good latch from the beginning. Many mothers are told the latch is perfect when, in fact, it is far from perfect. The latch can still be improved even in the older baby, but it’s not always easy. But sometimes it is. See the Increase intake of breastmilk and the video clips at the website

    Often, domperidone will increase the milk supply significantly and we use it often. However, you should not use it if you are pregnant. In the first place it won’t work if you are pregnant and although there is no evidence that it is worrisome to use during pregnancy, the absence of studies showing concern does not mean it is safe during pregnancy.

How Do You Know The Baby Actually Drinks At The Breast?

When a baby is getting milk (he is not getting milk just because he has the breast in his mouth and is making sucking movements), you will see a pause at the point of his chin after he opens to the maximum and before he closes his mouth, so that one suck is (open mouth wide - pause - close mouth type of suck). If you wish to demonstrate this to yourself, put your index or other finger in your mouth and suck as if you were sucking on a straw. As you draw in, your chin drops and stays down as long as you are drawing in. When you stop drawing in, your chin comes back up. This pause that is visible at the baby’s chin represents a mouthful of milk when the baby does it at the breast. The longer the pause, the more the baby got. Once you know about the pause you can cut through so much of the nonsense breastfeeding mothers are being told. Such as: Feed the baby twenty minutes on each side. A baby who does this type of sucking (with the pause) for twenty minutes straight might not even take the second side. A baby who nibbles (doesn’t drink) for 20 hours will come off the breast hungry. See the video clips at the website which show when a baby is getting milk (or not) and also how to latch a baby on and how to use compression.

Slow Weight Gain After Early Good Weight Gain, 2009© 
Written and revised (under other names) by Jack Newman, MD, FRCPC, © 1995-2016 
Revised by Jack Newman MD, FRCPC, IBCLC and Edith Kernerman IBCLC, 2008, 2009©