How is breast milk made?

Once breastfeeding is established, breast milk is produced on a supply and demand basis, but before that milk production is driven by hormones and your breasts actually start manufacturing milk when you’re around six months pregnant.

This first milk isn’t proper breast milk – it’s called colostrum and it’s a creamy, calorie-rich milk that provides your newborn with vital antibodies in his first few days of life.

The pregnancy hormone progesterone prevents your breasts from producing too much colostrum but in the days following your baby’s birth, pregnancy hormones drop rapidly – obviously they aren’t necessary any more! Now there are no pregnancy hormones keeping it in check, the hormone that promotes breast milk production – prolactin – can really get to work, and around three to four days after the birth you’ll notice the effects when your proper breast milk comes in. Your breasts will feel very full and hard when this happens.

Once your breast milk comes in and feeding is established, your hormones have less of a say in the matter – it’s your baby emptying your breasts that stimulates production of more milk. This also means that if he isn’t feeding well for some reason your milk production can slow down. If you want to increase your milk supply you need to ensure your breasts are fully drained at each feed – if they aren’t, it’s a good idea to express whatever’s left.

Your breast milk is made up of two component parts: watery foremilk, which quenches your baby’s thirst, and thicker, fattier hindmilk, which nourishes him and supports his growth. It’s essential he gets plenty of hindmilk so don’t take him off the breast before he has finished feeding (he’ll signal this either by falling asleep at the breast or coming off himself). Always offer him the second breast and if he doesn’t empty it, express the rest of the milk to drain it or ensure he latches on to this side first for his next feed.

Your newborn baby will probably need 10 to 12 feeds in each 24-hour period, and this will mean he feeds every three to four hours. If he’s feeding more often than this he may not be latching on properly – as a lactation consultant to check your technique. A minute or so after your baby latches on to feed you’ll get what’s called the let-down reflex. It’s a tingling sensation that signals the release of milk from your milk ducts and beware – once you’re a mom, the sound of any baby crying can cause it to happen so make sure you wear a couple of breast pads inside your bra to soak up any leaks! Keep in mind too that during the first week or so after the birth, breastfeeding stimulates your uterus to contract back down to its pre-pregnancy size, and this can cause cramping ‘afterpains’.

The information in this feature is intended for educational purposes only. If you have any concerns about your health, the health of your child or the health of someone you know, please consult with a doctor or other healthcare professional.