June 14, 2023

What is lactation and how does it work?

What is lactation and how does it work?

Written by Pamela Lim,  https://joyfulparenting.sg

Your breasts have been getting ready for breastfeeding since before you were born. At birth, the main milk ducts, which transport milk through your breasts, were already formed. During puberty, estrogen causes the milk glands to grow and swell, but it's during pregnancy that these glands kick into high gear.

Understanding how breastfeeding works can help you feed your baby.
Breasts are a fundamental aspect of female anatomy. They comprise different types of tissue, including fatty and supportive tissue, and glandular tissue responsible for milk production. The glandular tissue contains clusters of grape-like structures called alveoli, which produce milk. Milk then travels through ducts to the nipple, where it exits the breast through small openings. Understanding the intricacies of breast anatomy is crucial for women's health, and this article provides an overview of the workings of this vital part of the female body.


Producing milk is largely dependent on hormones. During pregnancy, hormones work to prepare the breasts for milk production.

Once the baby is born and the placenta is delivered, the pregnancy hormones decrease, and breastfeeding hormones take over, allowing milk production to begin.

Milk production begins during pregnancy, with colostrum production starting about three to four months into pregnancy. Mature milk will come in approximately two to four days after birth and will adjust to the baby's needs based on their appetite and how often they nurse. Some women may notice breast changes during pregnancy, such as tenderness and darkening of the nipples and areolas, but it's okay if you don't. Regardless, your body is still preparing to produce milk. 

During breastfeeding, the sucking action of your baby triggers the release of hormones into your bloodstream.

  • Prolactin, in particular, stimulates the milk-producing tissue, building up your milk supply.
  • Meanwhile, oxytocin causes the breast to push out or release the milk that has already accumulated. This release of milk is known as the let-down reflex or the milk ejection reflex.  

Here are some signs that can indicate the occurrence of the let-down reflex:

  • A tingling or sudden full feeling in the breasts, which can be intense and even painful.
  • Milk leakage from the other breast, as let-down happens simultaneously on both sides.
  • You might feel your uterus contract especially if this is not your first baby. 

Not all mothers experience the signs that indicate a let-down reflex. However, an unmistakable sign is a change in your baby's sucking pattern from a quick suck-suck to a rhythmic suck-swallow pattern as the milk begins to flow and your baby latches on more deeply. Therefore, it's crucial to observe your baby's feeding behaviour closely, even if you don't experience any other signs of the let-down reflex. While let-down may be more noticeable in the early stages of breastfeeding, it may become less noticeable over time. If your let-down reflex is slow to occur, there are measures you can take to help facilitate the process.

How do I know if it’s working?
You may experience some of the following signs of a let-down reflex:

  • A tingling sensation in the breast
  • A sudden feeling of fullness, which can be intense and even painful at times
  • Milk leaking from the other breast, as let-down occurs on both sides simultaneously
  • Feeling thirsty

However, some mothers may not experience any physical signs. Regardless, a clear indication of let-down is when your baby starts to suck deeply and rhythmically. The quick, shallow suck-suck pattern changes to a rhythmic suck-swallow as milk begins to flow.

You may also experience let-down if you see or hear your baby, or even just think about them. This reflex becomes conditioned over time, and certain cues such as a baby's cry can trigger the let-down even if it's not your own baby.

The concept of supply and demand in breastfeeding is simple:

The more your baby suckles and removes milk from your breasts, the more milk your body will produce. This ensures a constant and adequate supply of milk that meets your baby's needs.

When you start each feeding session by alternating breasts, you stimulate milk production in both breasts, ensuring a good supply of milk. Remember that there is always milk in your ducts, ready to be released during a let-down.

To sum up, breastfeeding is a natural and beneficial way to feed your baby. It provides essential nutrients and boosts their immune system, while also creating a special bond between you and your baby. Recognizing your let-down reflex and understanding the principles of supply and demand can help you establish a successful breastfeeding routine. Remember to take care of yourself by getting enough rest, staying hydrated, and seeking support when you need it. With patience and practice, breastfeeding can be a rewarding experience for both you and your baby.

Remember, if you ever feel unsure or need additional support, don't hesitate to seek lactation help. You can contact the Joyful Parenting Helpline at 6488 0286 or reach out to me, WhatsApp at 9271 3335, for postpartum and lactation home support.