How do your breasts make milk?

Your hormones have prepared your breasts during pregnancy. But after birth, it's the frequent and flexible removal of milk which carries milk production forward.

• Throughout pregnancy, the hormones progesterone and prolactin have been dramatically increasing in your blood stream. These hormones gradually ripen your breast's alveolar or glandular tissue. The hormone progesterone inhibits the milk-making action of prolactin.

• In the day after you've given birth and the placenta has left your body, your progesterone levels plummet. The action of prolactin on your milk glands is no longer blocked by the progesterone. The prolactin inevitably causes your milk to come in, usually within three to five days. Even without any suckling or pumping, these hormonal changes switch on the 'secretory activation' of your breasts. Secretory activation is under the control of your genetic code. This is the only period of your milk production which is predominantly controlled by your hormones.

The situation is different if you have a premmie baby, or if you are inducing lactation though.

How to help your breasts make plenty of milk for your baby from the beginning

Your hormones have worked for you, preparing the terrain of your breasts in the way the natural environment - rain and sunlight and humus, for example - prepare a good soil.

• But baby’s suckling at the breast (or if necessary, mechanically expressing your milk from your breast with a pump) is the planting of the seeds of your supply in those very first few days. This is the part of creating a milk supply which is predominantly under the control of cultural or health system knowledge. It's here that we might strike hospital hitches and glitches as you and your baby get started with breastfeeding.

• One study showed that eleven breastfeeds in the first twenty-four hours was associated with substantially more milk on the fifth day after birth, compared to seven breastfeeds in the first day. This is why knowing about frequent and flexible breastfeeding is important. Frequent and flexible breastfeeds might be quite different to what's often meant by demand breastfeeding.

Some believe it's important to stimulate production without relying on your baby in the first hours and days of life - that you should be pumping and hand expressing. This may be necessary if your newborn is affected by anaesthetic medications and sleepy, or has a medical condition. But otherwise, keeping the baby in skin-to-skin contact and knowing how to avoid any nipple damage and set up painfree transfer of the colostrum means you shouldn’t require hand expressing or pumping.

Your baby and your breasts are a resilient biological system. There's good reason to hope you can secure your milk supply even when it's not been possible to have baby at the breast as often as you might have wished in the first days and weeks. But breastfeeding tends to work much more easily long-term if your baby is feeding frequently and flexibly right from the beginning of life.

Recommended resources

What can you do to increase your milk production?