How breastfeeding works – from colostrum to full milk production

How does the body prepare for breastfeeding, what happens inside the breast, and how does breastfeeding work in the days after birth?<br>Understanding a little about the biology behind breastfeeding can make it easier to recognise why breastfeeding changes the way it does.

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How does the breast get ready for breastfeeding?

What changes can you see and feel in your breasts during pregnancy? Swipe to listen and read more about what happens in the breast.

 

Why do my breasts feel different during pregnancy?

Early in pregnancy, your body naturally begins preparing to make milk for your baby. Hormones released during pregnancy trigger these changes. This is why many people notice breast changes very early on — this is completely normal.

What changes can I feel in my breasts during pregnancy?

Many notice that the breasts get larger and may feel full, tight or tender. This happens because the blood flow to the breasts increases, and the milk-producing glandular tissue grows. For some, the darker skin around the nipple (the areola) becomes even darker. All of this is part of the body’s preparation for breastfeeding.

How do the nipples change during pregnancy?

Pregnancy hormones make the nipples more flexible. These changes happen especially towards the end of pregnancy, around the birth and in the early days after birth.
This flexibility helps your baby latch on and draw milk from the breast more easily.


No. There is no evidence that people with fair skin, red hair or freckles have more nipple problems when breastfeeding.

Many people have flat or inverted nipples — on both breasts or just one. This means the nipple does not protrude much or seems drawn inward.

For most, the hormonal changes around birth make the nipples soft and stretchy enough for the baby to latch well, and the nipples often stretch out more over time.

If you are concerned, talk to your midwife or health visitor.

If your nipples are very inverted, it may help to:

  • Keep your baby skin-to-skin after birth
  • Try a laid-back breastfeeding position
  • Gently draw out the nipple with a hand pump just before latching
  • If your baby still struggles to latch, a nipple shield might be an option — but always discuss this with staff at the maternity ward or your health visitor before using one.

When does milk production start during pregnancy?

Your body starts making colostrum (the first milk) halfway through pregnancy. Some people notice occasional drops of milk leaking; others never see any milk at all. Both are completely normal and have no connection to how much milk you will make later.

How does breastfeeding work in the first days after birth?

The journey of milk from the breast to your baby can seem mysterious. Swipe to learn about the let-down reflex, oxytocin and how milk volume changes in the first days.

When does the milk “come in”?

For the first few days, your body makes small amounts of colostrum. This amount is controlled by hormones — not by how much your baby suckles.

Around day 4, your milk “comes in.” At this point, milk production becomes driven by how often your baby feeds and how effectively the breast is emptied.


Colostrum is a thick, yellowish milk packed with antibodies that support your baby’s immune system. It contains exactly what newborns need and helps prepare their immature gut. It also stimulates their first bowel movement.

Is there enough colostrum for my baby?

Yes. Even small amounts of colostrum are usually enough. Newborns have tiny stomachs and need only small amounts at a time. Giving anything other than colostrum in the first days can disturb their appetite and interfere with the regulation of milk production.


During pregnancy and the first days after birth, milk production is controlled entirely by hormones. However, offering the breast frequently in the first days can help your mature milk come in sooner. Try offering both breasts at each feed.

How does the let-down reflex feel?

When your baby suckles, the hormone oxytocin is released. This triggers the let-down reflex, which makes the milk flow so your baby can drink.

Some people feel it as tingling or pins-and-needles, especially after the milk comes in around day 4. Others feel nothing at all — both are normal.


The let-down reflex can be slower if you are in pain, anxious or not fully relaxed. Try:

  • finding a more comfortable breastfeeding position
  • taking slow, deep breaths
  • listening to calming music or anything that helps you relax

Learn how to stimulate the let-down reflex:

Why do I get cramps when breastfeeding?

It is normal to feel afterpains during the first week after birth, especially if you have given birth before.

Suckling releases oxytocin, which helps the uterus shrink back to its normal size. This can be painful, but it is harmless and usually strongest in the first few days.

You may take pain relief if you need it.

 

 

How does breastfeeding work once the milk is in?

How do you know if your milk has come in, and what can you do to support milk production? Swipe to learn how breastfeeding changes after the first days of colostrum.

Breast fullness – a sign that milk is on the way

Between day 2 and 4, many people suddenly feel the breasts becoming fuller, firmer or warm.

This breast fullness varies — some feel it strongly, others hardly at all. Some newborns may find it harder to latch during this transition.

You may take pain relief if needed.


Breast fullness is caused by increased blood flow to the breast as milk production steps up. This can cause swelling and fluid in the tissue, making the breasts feel tight or tender.

To reduce fullness, you can:

  • breastfeed frequently, ideally 8 or more times a day
  • use cold compresses between feeds
  • gently move or massage the breast

 

If latching is still difficult:

  • try the “Reverse Pressure Softening” technique to soften the areola so the nipple protrudes more Place your fingers around the nipple and press inwards towards the chest for about 1–2 minutes. You may move your fingers and apply pressure again if necessary.

  • try a laid-back breastfeeding position, this allows the baby to come close to your body and achieve a better latch.

Breastfeeding positions

Breast fullness

How is milk regulated after the milk comes in?

Once your milk is in, production is guided by how often your baby feeds and how much milk is removed. Offer the breast whenever your baby shows hunger cues, that way your supply adjusts to your baby’s needs. However, it may take 4–6 weeks before supply and demand are fully balanced.


No. Avoid pumping unless advised by a healthcare professional. Pumping can increase milk production and worsen fullness. Instead, continue to breastfeed whenever your baby signals hunger. It may take 4–6 weeks before supply and demand fully match.

Contact your health visitor, doctor or maternity ward if you develop red, warm breasts, fever or signs of mastitis.

Mastitis

Should I feed from one breast or both?

In the first days, it is recommended to offer both breasts at each feed. Once your milk is in, it is best to let your baby finish feeding on one breast before switching.

If your baby pauses or unlatches to burp, offer the same breast again so your baby gets the richer, fattier milk at the end.

Some babies are full after one breast, while others need both. If your baby still seems hungry and refuses the first breast, offer the second.

How can I increase my milk supply?

If you feel you do not have enough milk, the most effective approach is to feed more often. Babies usually signal hunger more frequently when they need more milk. It may take a few days for your supply to increase.

How to increase your milk supply

Watch videos to help you get breastfeeding off to a good start

Find related content

Who can you contact?

If you experience challenges with breastfeeding – big or small – do not hesitate to seek professional advice. Swipe to see whom you can contact and when.

Who can you contact at the maternity ward?

You can contact the maternity-ward staff both during pregnancy and after birth.

Before birth, your midwife is the person to speak with about the early time with your baby and your thoughts about feeding – whether breastfeeding or bottle-feeding. If you have had previous breastfeeding problems, you can create a plan together.

Most maternity wards also offer antenatal classes, and your midwife can inform you about these.

After giving birth, you can receive help with breastfeeding from staff on the delivery or maternity ward while you are admitted.

All parents can also contact a breastfeeding hotline at their maternity ward within the first week after birth if they need help or guidance.

You can contact your municipal health-visitor service

The health-visitor service is available to all pregnant and new parents in Denmark. After birth, you will be offered free home visits with support and guidance to help you get a good start with your baby. Depending on your municipality and your stage in the process, different services and contact options may be available.

Some municipalities offer prenatal visits from a health visitor, where you can discuss breastfeeding, bottle-feeding, and preparing for life as a new family. Check your municipality’s website to see whether this is available where you live.

If you have special needs, you can contact the service to ask whether prenatal visits are offered to you.

Your health visitor will contact you and offer the first home visit. You can always call your municipal health visitor service for advice or guidance.

You can contact your GP if needed

Always speak with your doctor if you are pregnant or breastfeeding and need medical treatment. In most cases, there is a medication that is safe to use during pregnancy and breastfeeding.

Contact the on-call doctor or call 112 in an emergency

For sudden illness or worsening symptoms that cannot wait until your GP is available, or for minor injuries, you can contact the on-call doctor – or call 1813 if you live in the Capital Region.

In emergencies, if something is life-threatening or dangerous, call 112.

Contact volunteer breastfeeding counsellors

You can also contact volunteer breastfeeding counsellors if you need advice or support.There are two organisations in Denmark that offer this help: Forældre & Fødsel and Ammenet.The volunteers are mothers with breastfeeding experience, and both organisations follow the recommendations of the Danish Health Authority.

Get help from Forældre og Fødsel

Get help from Ammenet