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Slow Weight Gain After the First Few Months


Sometimes, babies who are doing very well with exclusive breastfeeding alone for the first few months, start not to gain as well after two to four months. This may be normal, because breastfed babies do not grow along the same growth curves as formula fed babies, and it may appear that they grow too slowly, when in fact, it is the formula fed baby who is growing too quickly.

Breastfeeding is the normal, natural, physiologic way of feeding infants and small babies. Using the formula feeding baby as the model of normal is irrational and leads us to make errors in advising mothers about feeding and growth.

In some cases, an illness in the baby may result in slower weight gain than is expected. 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). If he is not getting milk well, it is unlikely the baby has an illness, and more likely the mother’s milk supply is down. The most common cause of unusually slow weight gain after the first few weeks or months is that the mother’s milk supply has decreased.

Why would your milk supply decrease?

1. You have gone on the birth control pill. If you have, stop the pill. There are other ways of preventing a pregnancy besides hormones.

2. You are pregnant.

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.

4. You are using bottles more than occasionally. Even when the milk supply is well established, frequent bottles teach the baby a poor latch at a time when the baby expects rapid flow, even if you are giving the baby only breastmilk in the bottle. With slow flow, the baby may pull away from the breast, decreasing time at the breast even more, and decreasing breastmilk even more.

5. An emotional "shock" can, occasionally, decrease the milk supply.

6. Sometimes an illness, particularly when associated with fever can decrease the milk supply. So can mastitis. Luckily, illness in the mother does not usually decrease milk supply.

7. You are doing too much. You don't have to be a super mother. Let the housework go. Sleep when your baby sleeps. Let the baby nurse while you sleep.

8. Some medications may decrease milk supply - some antihistamines (e.g. Bendryl), pseudephedrine (e.g. Sudafed).

9. You are feeding one side only each feeding, so that he gets the high fat “hindmilk”. Remember, if the baby is not drinking, he’s not getting any milk and if he’s not getting any milk, he’s not getting hindmilk. “Finish” one side and if he wants more, offer the other.

9. A combination of some of the above.

10. Sometimes the milk supply decreases, particularly around 3 months for no obvious reason. It is likely, though, that you will find the reason in the next paragraph.

One more reason requires more explanation. In the first few weeks, babies tend to fall asleep at the breast when the flow of milk is slow (this slowing of the flow occurs more rapidly if the baby is not well latched on, since the baby depends on the mother’s “letdown” or milk ejection reflex to get milk). The baby will suck and sleep and suck, without getting large quantities at this point, but the mother may have a letdown reflex (milk ejection reflex) from time to time and the baby will drink more. When the mother's supply is abundant, the baby usually gains fine, though he may spend long periods on the breast despite the mother's abundant supply. However, by the time babies are six or eight weeks of age, younger sometimes, many will start to pull away from the breast when the flow slows down, often within a few minutes of starting to nurse. This is more likely to occur in babies who received bottles early on, but can occur even without the baby’s having received bottles. The mother will then likely put the baby to the other side, but then the baby will do the same thing. He may be hungry still, and may refuse the breast, preferring to suck his hand. He won't get those extra letdowns that give him a few extra gushes of milk that he would have had if he had stayed on the breast. So he 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 you see what may happen. It doesn't always happen this way, and many babies may gain even if they do spend only a short period of time on the breast. They may still pull off and suck their hands because they want more sucking but if their weight gain is good, there is no need for concern.

The way to prevent this is to get a good latch from the very first. However, many mothers are being told the latch is good even if it isn't. A better latch can help, sometimes even at a later date. Using compression will often keep a baby drinking (see Handout B: Protocol to Increase Breastmilk Intake by the Baby).

Sometimes domperidone will increase the milk supply significantly. Do not use it if you are pregnant, however (Handout 19a: Domperidone-1 and Handout 19b: Domperidone-2).

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). 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 also the videos at The videos show how to latch a baby on, how to know a baby is getting milk, how to use compression.

Questions? (416) 813-5757 (option 3) or or my book Dr. Jack Newman’s Guide to Breastfeeding (called The Ultimate Breastfeeding Book Of Answers in the USA.)

Handout #25: Slow Weight Gain After the First Few Months . January 2005

Written by Jack Newman, MD, FRCPC. © 2005

This handout may be copied and distributed without further permission, on the condition that it is not used in any context in which the WHO code on the marketing of breastmilk substitutes is violated.

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