How Milk Supply Really Works

Milk supply isn’t magic, it’s physiology. 

So, I’ll be honest—it bothers me when parents are told early on that they simply “don’t make enough milk,” often without an assessment, and sometimes without even an explanation. 

Understanding how milk supply is established and maintained can reduce stress, provide more feeding options, and give you back control over your experience. And I want that for you!

So with this post, I’m letting you in on the “secrets” of milk supply—that shouldn’t really be secrets at all!

HI! I’M DANIELLE MONDESIR (M.S., CCC-SLP, CBS)

My goal is for you to have a safe, happy baby. So you can feel safe and happy as a mom. I’m Danielle, a speech-language pathologist, Certified Breastfeeding Specialist, and the founder of Desired Pediatric Therapy Services. I created Desired Pediatric Therapy Services to ensure that children receive high-quality, child-centred therapy, and their parents get the support they need to navigate the journey. Without judgment, waitlists, frustration, or that feeling of being dismissed! My goal is to empower families, bridge communication gaps, and make therapy a truly impactful experience from the very start. Because I know that when parents are supported, healthy, and happy, everyone thrives.

How Milk Supply Works

If you’re reading this, you’re probably at least a little sleep deprived. So let me get right into it:

Milk supply works on supply and demand. The more milk your baby drinks (or you pump), the more your body thinks is needed, and the more you will produce. 

If giving your baby breastmilk is the goal, early and frequent breastfeeding or pumping sessions will be your best friend during the first two weeks postpartum (called the “calibration phase” of feeding). If possible, avoid skipping feeds or supplementing unnecessarily during this phase, as these things can affect your overall milk supply—and that’s a big if because there’s more to your postpartum and parenting experience than just breastfeeding, like sleep and protecting your mental health.

Dive Deeper: How Milk Supply Works by La Leche League

How Do I Know If I’m Making Enough Milk?

According to the U.S. Department of Agriculture, signs that your baby is getting enough milk include sufficient wet and dirty diapers, visible swallowing during feedings, steady weight gain, and a general sense of ease and contentment after they feed. Things that don’t matter as much? How your breasts feel, the duration of your feeds, cluster feeds, or how much you can hand-express.

That said, even if your baby is getting enough milk overall (or has in the past), it’s common for your supply to dip from time to time, often due to:

• Missed or shortened feeds
• Switching breasts too early
• Illness or stress
• Hormonal shifts such as menstruation and or birth control
• Cluster feedings
• Developmental changes in your baby

These dips lead some parents to believe they have a low milk supply, when it’s not actually about their ability to produce milk at all. If this happens to you for whatever reason, don’t panic! Aim for more frequent nursing or pumping sessions, and your body will likely respond by producing more milk.

What Causes Low Milk Supply? 

Low Milk Supply isn’t the same as the “dips” I described above—it’s when you’re consistently producing less milk than your baby needs. 

Most often, low supply is the result of what we call “insufficient removal of milk,” which stems from fixable issues like latching problems, ineffective feedings, or formula supplementation without breast stimulation. But it can also be impacted by stress and certain underlying conditions, like:

• PCOS (Polycystic Ovarian Syndrome), which can affect milk-producing glandular tissue and hormones.
• Thyroid conditions, such as hypothyroidism or hyperthyroidism, which can delay or suppress lactation hormones.
• Gestational diabetes or insulin resistance which may interfere with hormonal signalling post-birth.
• Retained placenta or significant blood loss at birth, which may “lock” the hormonal transitions your body relies on to cue full milk production.
• Insufficient glandular tissue, also known as IGT, which is a structural issue that results in fewer milk-producing cells.
• Previous breast surgeries may impact milk, ducts, or the nerves needed for letdown, depending on the type.
• Fertility treatment or hormonal imbalances, which can impact certain hormones that affect milk supply.

Obviously (at least, I hope it’s obvious!) none of these underlying conditions are your fault. But if you have any of these conditions, catching them early with the help of a lactation consultant can dramatically change the course of your breastfeeding journey.

How To Increase Your Milk Supply

Whether you’re experiencing a dip or have always had low supply, no special tea or cookie will fix. (Sorry to burst our collective bubble!) Here are a few things that have been shown to help:

• Feed often! Aim for 8 to 12 feedings every 24 hours for newborns.
• Prioritize skin-to-skin contact in the first hours and weeks.
• Hand-express colostrum while you wait for your milk to “come in.”
• If your baby isn’t latching effectively or you’re separated, pump!
• Avoid early or unnecessary formula unless it’s medically indicated or it’s your preference (it’s okay if it’s your preference!).
• Practice breast compressions during feedings or pumps.
• Rest (as much as you can, considering), eat enough, and stay hydrated.

If reading this list feels overwhelming, please know that you don’t have to do this alone. You can always reach out to an International Board-Certified Lactation Consultant (IBCLC) who can help. 

Getting support within the first 48 to 72 hours can make a big difference—it’s never too early.

References

1. How Milk Production Works by La Leche League
2. Increasing Milk Supply by La Leche League
3. Breastfeeding Attachment by Global Health Media