Understanding Milk Supply: How Breast Milk Production Works and What Can Affect It
Worried You Don’t Have Enough Milk?
Feeling anxious about milk supply is one of the most common breastfeeding concerns for new moms — and also the main reason many stop breastfeeding earlier than planned.
Yet, true low milk supply is rare. Most mothers produce enough milk once they understand how supply works and get the right support.
If you’re only wondering whether your experience is normal, check out our article on false alarms for low milk supply — it might put your mind at ease.
How Breast Milk Is Made
Before you can understand why milk supply sometimes seems low, it helps to know how your body produces milk and what influences this natural process.
Hormonal Kickstart
Milk production begins during pregnancy. As your body prepares, you might notice your breasts growing, nipples and areola darkening, and veins becoming more visible.
After birth, when the placenta is delivered, there’s a sudden drop in progesterone and estrogen, allowing prolactin levels to rise. This hormonal shift triggers your milk to “come in” about 3–4 days after birth.
The Two Key Hormones in Milk Production
- Prolactin: Stimulates the milk glands to produce milk.
- Oxytocin: Causes milk to flow (“let-down”) and also strengthens bonding and relaxation — often called the love hormone.
Skin-to-skin contact, looking at your baby, and especially latching and suckling all trigger the release of these hormones, which keeps milk production active.
The Big Misunderstanding About Milk Supply
Many mothers think their breasts must “fill up” and the baby must “empty” them during feeds.
In reality, you make milk while your baby is feeding. Your breasts are never truly empty — milk is continuously produced in response to stimulation and demand.
When your baby latches and suckles, messages are sent to your brain’s pituitary gland to release prolactin and oxytocin. These hormones then drive milk production and flow.
In the early weeks, your breasts may feel full between feeds, but this fullness should reduce over time. Mature lactation means milk is made on demand, not stored in advance.
The first mistake actually comes with calling it ‘supply’, as this implicates that it can run out. As Dr. Christina Smillie explains, milk is like any other body fluid — you don’t run out of tears or sweat, and similarly, your body can make milk whenever it’s needed.
Establishing and Maintaining Milk Supply
Two key factors determine how well your milk supply is established and maintained:
- Effective Breast Stimulation: A deep, comfortable latch and regular suckling.
- Frequent and Complete Emptying: Feeding on demand and allowing baby to finish each breast.
If either of these factors is disrupted, milk production can temporarily decrease.
Common Factors That Interfere with Milk Production
These issues usually happen together and can lead to low supply if not addressed early:
- Incorrect latch or positioning (often shown by nipple pain)
- Tongue-tie or oral anatomy issues in baby
- Using a nipple shield incorrectly
- Not feeding on demand or spacing feeds too widely
- Supplementing with formula without expressing to replace missed breastfeeds (the “top-up trap”)
- Limiting feed times (e.g., stopping after 15 minutes per side)
These problems often form a chain reaction: poor latch → baby feeds poorly → top-ups introduced → supply decreases.
Early help from a certified lactation consultant can prevent or reverse these challenges.
The First Weeks: Your Golden Window
The first 2–3 weeks after birth are critical for establishing milk supply.
If breastfeeding is interrupted during this period, supply may be harder to build later — but it’s never too late to improve things with the right help.
If you’re beyond this window and experiencing difficulties, don’t worry — support and techniques can still make a difference.
Medical Factors That Can Affect Milk Supply
Some true medical conditions can influence how much milk your body produces, though many can be managed effectively:
- Premature birth (especially if breast tissue was still developing)
- Thyroid disorders (especially underactive thyroid — ask your doctor to recheck levels postpartum)
- Polycystic ovarian syndrome (PCOS)
- Insulin resistance or diabetes
- Previous breast surgery (particularly reduction procedures)
- Hormonal contraception
- Certain medications
- Rare breast glandular tissue deficiencies
With guidance from your healthcare provider, most of these can be addressed to support continued breastfeeding.
How to Know If Your Baby Is Getting Enough Milk
Many moms misinterpret normal baby behaviors (frequent feeding, fussiness) as signs of low supply. But there are only two reliable indicators:
- Nappy output: 5–6 wet nappies and regular dirty nappies daily.
- Steady weight gain:
- No more than 10% weight loss by day 3
- Regain birth weight by 2 weeks
- Consistent gain along WHO breastfeeding growth charts thereafter
If your baby meets these, your milk supply is likely just fine.
For Pumping Moms
If you’re expressing milk and worried about low output, check:
- Pump parts (valves, membranes, and tubing) for wear
- Flange fit and comfort
- Pump suction strength and cycle speed
If problems persist, contact a demo centre or email info@allthingsbreastfeeding.co.za for local troubleshooting and lactation support.
Key Takeaway
Most mothers can produce enough milk when breastfeeding is well-managed and supported. Understanding how milk production works — and what can disrupt it — empowers you to trust your body, respond to your baby’s cues, and enjoy your breastfeeding journey.
