How Does My Body Produce Breast Milk?

Hormonal changes in your body start preparing you to produce milk, also known as lactating, in mid to late pregnancy.2 From that time through delivery and breastfeeding, your body goes through three stages of lactogenesis, or milk production:1,2

  • Stage 1. This stage starts during pregnancy and can last up to 96 hours after your baby is born. Estrogen and progesterone levels rise, making your milk ducts multiply and enlarge.1 Small bumps on your areola called Montgomery glands start to secrete an oil that protects the nipple and may encourage your baby to latch.1 Your body also makes colostrum during this stage.1
  • Stage 2. This stage begins within a few days of giving birth and lasts through approximately the first month of milk production.1 After your baby is delivered, your estrogen and progesterone levels drop and prolactin, the hormone that spurs milk production, rises.1 This is when milk volume increases, which is often referred to as the time your “milk comes in”.1
  • Stage 3. This stage is the rest of the time you experience lactation and lasts until you stop breastfeeding or expressing breast milk.1 The volume of breast milk produced is maintained through a supply-and-demand mechanism: you can raise production by expressing milk more often or in greater quantaties.1

Does Breast Size Matter for Producing Breast Milk?

Whether you're a B cup or a double D, it's possible to both breastfeed and produce enough breast milk to feed your baby. The size of your breasts doesn’t correlate to how much milk you’re capable of producing.1 So even if your baby is in a growth spurt and nursing more often, your body will try to "keep up".2 Remember, mothers of twins and even triplets may have enough milk supply to breastfeed successfully. Nature designed a perfect supply-and-demand system. The more your baby stimulates your breasts by suckling and feeding successfully, the more milk you may produce.3

There are many different sizes and shapes of nipples that will allow for successful breastfeeding.3 Some women may have flat or inverted nipples (nipples that turn in), which may make it more challenging to breastfeed. If you have difficulty getting your baby to latch, please see a lactation consultant.

How Much Breast Milk Does My Baby Need?

You’ve found your breastfeeding hold, your baby latches, but are you producing enough milk? Providing all the nutrients baby needs during their first days of life doesn’t mean providing lots and lots of breast milk. Baby’s tummy only holds a teaspoon or two at birth.4 Ten days later, their tummy can hold around two ounces.4

If you’re unsure if your baby is getting enough breast milk, two of the biggest telltale signs include appropriate weight gain and wet diapers. It’s common for babies to lose a little bodyweight the first few days after birth, but they’ll put it back on—and then some—in the first two weeks of life.4 By day six, your baby should have six or more wet diapers a day (often with poop) if they’re feeding well.4 If these are missing, it is recommended to see your care provider.

What Causes Low Milk Supply—and How Can I Produce More Milk?

If you know you’re producing less milk than your baby needs—or you simply want to prevent that from happening—understanding what can cause low milk supply is key. Not producing enough milk for breastfeeding can be caused by:5

  • Breast surgery that affected the mammary glands
  • Certain birth controls or other medications
  • Chronic conditions like diabetes
  • Drinking alcohol or smoking
  • Giving formula exclusively instead of breastfeeding or expressing breast milk
  • Limiting the number of times baby feeds
  • Not getting enough restful sleep
  • Starting solid foods before the four-to-six-month range

If you feel the need to increase your breast milk supply, follow these tips:4

  • Empty both breasts during (or after) each feeding. If your baby is full before your breasts are empty, go ahead and express the rest.
  • Feed every time baby is hungry. The key to producing milk is feeding—or, at least, removing breast milk from the breasts.
  • Pump or express between feedings. Like breastfeeding when your baby is hungry, this signals to the body to keep breast milk production up.

You can also explore power pumping and cluster feeding methods to raise milk supply.

For additional support on your parenting journey, visit Enfamil A+ Canada.