What’s all the fuss about foremilk vs hindmilk?
Studies show that the milk a baby gets earlier in a feeding is lower in fat content (foremilk), and the milk later in the feeding is higher in fat (hindmilk) (1). A side effect of this discovery is that parents are often encouraged to leave their babies on the first breast for long periods of time, sometimes only doing one-sided feedings, to try and ensure that they get the hindmilk.
Here’s the tricky bit: there is no magical moment when the milk changes from foremilk to hindmilk. The fat changes on a continuum throughout the feed, and is related to how empty the breast is. If a baby feeds on one side, and then comes back five minutes later, are they drinking foremilk or hindmilk? Well, it is the early milk of that new feeding (the foremilk), but the fat content will look more like the last milk they got five minutes ago (the hindmilk). What if they come back an hour later? Or three? Breast fullness and emptiness is relative, and what matters most for the baby’s growth is overall milk consumption.
Milk Flow and One-Sided Feedings
Babies respond to how quickly milk flows, and milk flow often follows a pattern during a feeding. It takes a few minutes for the breast to start flowing at the beginning, then the milk reaches its peak with the first letdown (when you may see your baby swallowing rapidly), which slowly eases up until it stops again (and you will see little sucks instead of drinks). If your baby keeps sucking they may trigger another letdown, which increases the flow of milk again. Each successive letdown tends to be less forceful and shorter as the feed goes on and the baby gets more and more full.
In general, babies prefer faster flowing milk. This is at the heart of why some babies develop a preference of bottles over the breast (often called “nipple confusion”), and why your baby may prefer your faster flowing breast over the other one.
As the feeding goes on, and they wait longer and longer for the next letdown, younger babies will tend to fall asleep, and older babies will start to pull, twist, tug, or hit the breast. If you add a breast compression, which temporarily boosts the flow of milk, often that sleepy baby will wake right up, and the squirmy baby will settle down and drink again.
What About Finishing the First Breast?
There is a common refrain of “finish the first breast first”. Research shows that babies take, on average, 60-75% of the milk available in the breast (2), so the breast is never really finished. If we know that babies prefer faster flow, and that flow slows down over the course of the feeding, then it becomes clear why one-sided feedings may be problematic. The young baby may fall asleep on the first side, meaning that further letdowns aren’t triggered. Older babies may pull and fight the breast, causing pain, and often delatching. In both of these cases the babies are no longer getting foremilk, hindmilk, or any milk for that matter, because they have both stopped feeding at the breast.
What is the solution?
The solution is making sure that the baby’s time spent at the breast is actually time spent drinking. Taking measures to boost the flow of milk can help to make feedings more efficient and enjoyable for everyone involved.
By watching your baby’s chin for pauses as they drink, we can tell if they are getting milk at the breast. Read more about sucks vs drinks here. As the feed goes on and drinking slows down, longer periods of little sucks may take place. This is when we can take action to keep the baby drinking by using breast compressions and offering the other breast. Switching back and forth between the breasts is often a necessary tactic, especially in the evening or during cluster feedings. The breast they are currently feeding on is often flowing slower than the breast that has had a break, so when one side isn’t leading to drinking it’s time to switch to the other. In most cases faster flow=more active drinking.
What happens when using breast compressions and switching sides isn’t enough? Stay tuned for more information on keeping babies actively feeding at the breast.
- Saarela T, Kokkonen J, Koivisto M. Macronutrient and energy contents of human milk fractions during the first six months of lactation. Acta Paediatr. 2005;94(9):1176–1181.
- Kent JC, Mitoulas LR, Cregan MD, Ramsay DT, Doherty DA, Hartmann PE.Pediatrics. Volume and frequency of breastfeedings and fat content of breast milk throughout the day. Paediactrics. 2006;117(3):e387-95.