As a new parent, it’s easy to get caught up in worrying about milk supply. Is your baby getting enough? Are you making too much or too little? In a world that is a constant social media avalanche of conflicting advice, it can be hard to know what’s truly normal. The truth is, your milk supply is a very dynamic system that probably doesn’t work the way you expect. Understanding how it works can help you feel more confident and less stressed about the process.
The Letdown: How Milk Flows From Breast to Baby
A key concept to understanding your milk supply is the letdown, or milk ejection reflex. This is the physiological process where milk is released from the milk ducts in your breast and becomes available to your baby. At the start of a feeding, a baby’s vigorous suckling on the nipple sends a signal to your brain. In response, your brain releases the hormone oxytocin, which causes the tiny muscles around your milk ducts to contract and push milk forward.
You may feel a letdown as a tingling, tightening, or even a sudden rush of milk. For some, it might feel like a pinprick sensation, while others feel nothing at all. All of these are normal. While a single letdown releases milk for your baby, it's not the only letdown you will have during a feeding. An average letdown produces about an ounce of milk. Next time you pump and get one ounce per side, you’ll know- this is an average letdown.
Because a baby typically needs more than one ounce per feeding, your baby’s suckling will naturally cause another letdown. Babies receive about 80% of their milk from the letdown, while the remaining 20% is obtained between letdowns.
The Snacking Pattern: Here an Ounce, There an Ounce
Babies are remarkably smart at managing their milk intake. On average, a mother will have two to three letdowns during a typical feeding from both sides. This is why babies often switch between periods of vigorous swallowing and slower, more rhythmic suckling. They are just working their way through the letdowns, ensuring they get all the milk they need. A baby might start with fast, shallow sucks to stimulate the first letdown and then switch to long, deep pulls once the milk is flowing. When the flow slows again, they will change their sucking pattern to get another letdown.
Pumping with the Letdown in Mind
Understanding the letdown is also helpful when you're pumping. It’s important to know what an average letdown is, so you can know what you can expect your pump yield to be. Social media tends to set the bar unnaturally high, showing multiple full bottles of milk per pumping session, but the truth is getting that much milk would be considered an oversupply in most cases.
Most breast pumps have a stimulation phase and an expression phase. The stimulation phase uses a faster, lighter suction to mimic a baby’s initial sucking and trigger a letdown. Once your milk starts flowing, you switch to the slower, deeper expression phase. When your milk flow slows down, you can go back to the stimulation phase for a minute or two to trigger another letdown and get more milk. By repeating this cycle, you can mimic a baby’s feeding pattern and often get more milk in a single pumping session than you would by just running the expression phase.
Setting achievable goals for your pumping and understanding your baby’s normal feeding patterns can help you trust that your body can give your baby everything they need to thrive.
