Oversupply Problems

What used to be called foremilk–hindmilk imbalance is now called lactose overload or secondary lactation intolerance.[3] (This is very different from primary lactose intolerance, which is extremely rare in babies, as lactose is the main carbohydrate in human milk.) The terms “foremilk” and “hindmilk” cannot be defined because the breasts only produce one kind of milk. However, the fat content does change from feeding to feeding and throughout the duration of a feeding, based on how the milk is released from the breast. Research shows that the breast milk consumed by a baby typically contains more fat towards the end of a feeding.[4,5]

Lactose overload often goes hand in hand with oversupply. When the breasts are very full due to excess milk production, the milk that comes out first is relatively low in fat compared with the milk that comes when the breast is emptier. Thus, the baby gets full before the breasts are empty enough to release the higher fat milk at the end of a typical feeding. As a result, the enzyme that digests the milk sugar lactose, lactase, becomes overwhelmed and cannot digest all of it. 

This leads to excess lactose remaining in the baby’s intestines, which can cause an osmotic effect that draws in water into the gut, and fermentation of the lactose by gut bacteria, leading to gas and frequent watery stools.[6] More than 8 heavy wet diapers a day, rapid weight gain, and very frequent greenish watery stools are tell-tale signs. (Note that it is normal for most babies have some amount of gas and occasional greenish watery stools. If everything is going fine with breastfeeding, your baby is gaining weight appropriately, and they do not seem to have constant abdominal distress, atypical diapers are not necessarily a problem.)

Lactose overload is a temporary condition that can be treated by reducing the mother’s milk production to levels appropriate for her baby’s appetite. This will allow the baby to receive the appropriate ratio of carbohydrates such as lactose, fats, and proteins. This also resolves the lactose overload discomfort and can assist in reaching the end of feedings with higher fat milk. 

For babies who are struggling with painful gas and explosive watery stools, massaging the breasts may be helpful for increasing the fat content of their milk.[7,8] Make sure to consult with your baby’s physician if your baby develops any of these symptoms before assuming that this is a problem with lactose overload, as there are other medical issues such as GERD (gastroesophageal reflux disease) that can be involved.

• You can also slow your flow by making a V-shape with your index and middle fingers (scissor hold) and lightly pressing on your breast near your areola to slightly compress your milk ducts. As your baby drinks, gradually reduce the pressure and then remove your fingers as the flow slows down, as constant pressure on your breasts can lead to plugged ducts.
• Some mothers find that nipple shields take the edge off the speed of the first letdown; they can be removed for the remainder of the feeding.
• Any time your baby has trouble managing the flow, take him off, let the breast spray into a towel, then put him back on once the spray has slowed or stopped.

Mothers with oversupply should be cautious about using products such as silicone passive pumps that collect leaking milk from the breast that is not being used while feeding; these encourage more milk to flow out of the breasts, thus worsening the oversupply. Milk that leaks out naturally can be collected and stored if desired, using sanitary collection and storage guidelines.