Breastfeeding: understanding its stages and physiology through to weaning

The stages of establishing breastfeeding

The phases of lactogenesis

It may seem surprising, but from the 5th–6th month of pregnancy you may already have a small amount of breast milk. This stage is called lactogenesis I. After the birth comes lactogenesis II, with an abundant production of breast milk, popularly known as your “milk coming in”. Finally comes galactopoiesis, or lactogenesis III: the process that keeps milk production going once breastfeeding is established.

Unlike other mammals, lactogenesis II, when your milk comes in, starts a few days after the birth. These days are a critical period for breastfeeding, as this is when many breastfeeding difficulties begin.

How milk synthesis, secretion and release are regulated

Although it is the mother's hormonal changes after birth that trigger the breast milk coming in, it is frequent suckling and emptying of the breast that keep it going. When it comes to the processes of production and ejection, several regulatory systems are at work, all of them strongly influenced by your baby's suckling and other stimulation of the nipple.

Prolactin

During pregnancy, in response to rising levels of oestrogen and progesterone, the pituitary gland produces prolactin. This hormone stimulates milk production. During pregnancy, however, it stays inactive because progesterone and placental lactogen prevent prolactin from binding to its receptors (competitive binding). After the birth, the levels of these two hormones drop quickly, prolactin is no longer blocked and breast milk secretion begins.

After the birth, prolactin is released in pulses in response to various stimuli, the most effective being suckling at the nipple. Prolactin levels in the blood peak about 20–30 minutes after suckling, so its most important effect is to make breast milk for the next feed. Hence the saying, “the more suckling, the more milk”. This effect is especially important while breastfeeding is being established, because after a few weeks there is no link between the amount of prolactin and the amount of breast milk produced.

Oxytocin

Oxytocin is released in response to stimulation of the nipple, through suckling or touch, and in response to pleasant physical, visual, sound or emotional cues, usually related to your baby.

This hormone makes the cells surrounding the alveoli contract, producing the milk ejection reflex (let-down), which helps the breast milk move along the ducts towards the nipple.

This process happens continuously during suckling and refills the ducts as they empty. Bear in mind that stress, anxiety and other sudden unpleasant physical stimuli can block the oxytocin let-down reflex.

Other regulating factors

When breast milk is retained in the alveoli, the pressure inside them rises and affects how the alveolar cells work. It can also compromise blood supply and make it harder for hormones to arrive, slowing down milk production when the breast is full or the gland isn't being drained effectively.

Your baby cancels out these inhibiting effects by draining your breast properly. In this way, breast milk production adapts to your baby's needs, from one feed to the next and separately for each breast.

Lactogenesis II: your milk coming in

As we've mentioned, lactogenesis II, or your milk “coming in”, begins after the sharp drop in progesterone and placental lactogen after the birth. During this phase, the production of the components of breast milk increases, which makes the breasts bigger, warm and tender. There is no link between how intense these symptoms are and how much breast milk you go on to produce.

Clinically, the “breast milk coming in” happens around the third day after the birth, but up to 25% of mothers notice it after 72 hours. At that point, your baby takes around 20 ml of breast milk at each feed.

Factors that help lactogenesis and breastfeeding

• Early skin-to-skin contact between mother and baby.
• Starting breastfeeding within the first hour after the birth.
• Frequent breastfeeding.
• A good latch (mouth to breast).
• Draining the breast properly.
• Early and frequent suckling in the first few days.

• Obesity and poorly controlled insulin-dependent diabetes play a part in the delayed milk coming in seen in mothers with diabetes and obesity.
• Retained placental fragments, because of the progesterone and placental lactogen they contain, can inhibit lactogenesis II.
• Difficult births and stress are another cause, and the one most closely linked to stopping breastfeeding early. In the mother, stress blocks the oxytocin reflex; in the baby it can affect how they adapt to the breast or lead to weak suckling.

Galactopoiesis, or milk supply settling down

Once abundant breast milk production has started, the amount depends on how effectively and how often the breast is drained. As well as volume, suckling can partly regulate the composition of the milk. Breast milk is made continuously and is stored until the next feed inside the alveoli and the duct system. Breastfeeding guide.

Weaning: how to do it

As with everything in life, there will eventually come a stage when your breastfeeding journey comes to an end, and it's important to understand how to go about it. It's well known that the WHO and clinical guidelines recommend exclusive breastfeeding for 6 months and then breastfeeding alongside other foods up to two years, and it has even been described up to 7 years. There's no reason to stop at a particular age, but of course this decision is entirely yours, and at Happymami we'll be by your side with the best solution for whatever you decide.

Circumstances that can lead to the end of breastfeeding, or “weaning”

So, what can lead to weaning? Every case is unique and all are worthy of respect; the most important are the mother's decision, the baby's own choice, illness in the mother or baby, or work. Remember that you can read our posts on maternity leave and paternity leave (both about the rules in Spain; rules differ from country to country, so check your own employer and national rules).

Types of weaning

In theory, there are 4 types of weaning, depending on the reason for it.

• Unavoidable weaning for medical or other reasons. In reality, there are few illnesses and medicines that are incompatible with breastfeeding. You can always check the e-lactancia.org website to clear up any doubts about a medicine. Guide to breastfeeding problems
• Child-led weaning: you'll see your baby gradually decide to stop feeding. Sometimes this can be influenced by a new pregnancy, which can change the taste and amount of breast milk.
• Mother-led weaning: your own decision to carry on breastfeeding or not is legitimate, and you shouldn't accept judgement for making the choice that feels right to you. Always find out the pros and cons and you'll make the best decision for you. As a personal note: you can't change what people think, but you can change how it affects you, and you're doing brilliantly.
• Forced weaning for external reasons, social or family-related, that have nothing to do with the mother and child. Remember that the decision to carry on breastfeeding or not is yours alone.
• Gradual, unnoticed weaning. Feeds become further and further apart until your baby weans.

Feelings that can come up during weaning

Many feelings can come up during weaning, such as guilt and sadness, and that's completely normal. Lean on your midwife: they'll support your decision and help you with your situation, so you can cope better and understand the process. On the one hand, if weaning was your decision, your baby may have tantrums or cry inconsolably. This is because, as a breastfed baby, when they're hungry they think of the breast they love and that satisfies them, and of course they don't understand why they can't have it. On the other hand, if breastfeeding was causing you stress and making your bond with your baby harder, it will feel like a relief for both of you.

Guidelines for weaning

There are several ways to wean, and if you talk to other mums, each will have used a different method; it worked well for some and not for others. Every case is different and you should always adapt these recommendations to your own situation. On the one hand, if you wean overnight, your doctor may recommend specific medication to stop the milk. If, on the other hand, you wean gradually, feeds will become further apart over time and breast milk production will decrease.

How to wean gradually

There are several strategies you can choose from to wean, as recommended by the Spanish Association of Paediatrics (AEP):

• Don't offer, don't refuse. If your child doesn't ask for the breast, don't offer it. If they ask, don't refuse.
• Space out feeds. Distract them in other ways (at the park, playing with them, reading a story, rocking them to sleep in your arms…).
• Offer other food at the times they usually ask for the breast. Anticipate their need.
• Agree on feeds with your child. Tell them “only at home”, “only 3 minutes”, “only one side”, “only at bedtime”, etc.
• Talk to them and agree on weaning together, explaining that “mummy doesn't want to give milkies any more”.
• If there's pain, express milk regularly to avoid complications such as mastitis. If weaning is going well, this won't be necessary.

False weaning:

Remember that there are breastfeeding crises, and they don't mean weaning. These nursing strikes are completely normal: you'll see your baby lose some interest in feeding, for example when they're poorly, after a fright during the previous feed or because they've been forced to feed. Why is my baby crying?

As we've seen, several factors influence how milk is made and released, and all of them are key to establishing breastfeeding properly. Prolactin and oxytocin are the key hormones in this process, but the whole system needs to work together. At Happymami, we'd like to remind you that it can be hard at the beginning, but later it becomes much easier. Trust yourself, your baby and the health professionals around you, such as your midwife, who will help you achieve your breastfeeding goals.

Benefits of breastfeeding

Breast milk is unique. It's a living fluid specially designed for the human baby that changes from feed to feed, day to day and month to month to meet your baby's needs. It also provides active defences against infection. If you're interested, you can find out more about the importance of breast milk.

Benefits for your baby

• It protects against respiratory infections, ear infections, gastrointestinal infections and even urinary infections.
• It protects against Sudden Infant Death Syndrome (SIDS).
• Breastfeeding gives babies physical contact, which helps them feel safer, warmer and comforted.
• Breastfed children have better dental development, with fewer orthodontic problems and less tooth decay.
• It boosts intellectual development, because breast milk contains specific components that are vital for brain development.
• Breast milk is easier to digest and has long-term positive effects on the child's health, lowering the risk of allergies, diabetes, coeliac disease, inflammatory bowel disease, obesity, high blood pressure or high cholesterol.
• It seems to offer some protection against lymphomas and some other types of cancer.
• Human milk is the food of choice for all babies, including premature babies, twins and babies who are ill.

Benefits for mum

• It helps prevent postpartum haemorrhage, as the baby's suckling helps the uterus return to its original size, and it reduces the chance of anaemia.
• It helps you get back to your pre-pregnancy weight.
• It brings emotional wellbeing and a unique opportunity for bonding between mother and child.
• It reduces the risk of breast and ovarian cancer.
• It improves the calcium content of your bones by the time you reach the menopause.

Benefits for society and the environment

• It's free. It saves money on formula milk.
• By reducing infections and how severe they are, it cuts medical costs and the work and family problems these illnesses cause for parents and society. It reduces the use of human and material healthcare resources, and if children do get ill, they recover sooner.
• Breast milk is a natural resource that doesn't pollute and protects the environment: it produces no waste and needs no packaging or special processing that uses energy or produces CO2 emissions.

Are there any reasons not to breastfeed?

There are very few situations in which breastfeeding is contraindicated. This means that almost all women can feed their babies their own breast milk if they choose to. The contraindications are:

• A mother with HIV infection: in our setting this is considered a true contraindication.
• Galactosaemia: a condition very few babies are born with, which stops them digesting the lactose in milk, so feeding with breast milk is contraindicated.

How do I prepare my breasts for breastfeeding during pregnancy?

You don't need to do anything to prepare your breasts for breastfeeding during pregnancy. What is a good idea is to find out as much as you can about it. You can go to antenatal classes run by midwives. Look for help, support, advice and information from professionals with breastfeeding expertise (nurses, midwives, obstetricians, paediatricians, GPs…). Ask about anything you need or anything that worries you. Talk to your partner and share the information so you can decide together. Talk to other family members to set up a small support network at home, so you can relax and enjoy breastfeeding while you and your baby get to know each other.

Starting breastfeeding after a vaginal birth or a caesarean

It's very important to start breastfeeding as soon as possible after the birth, whatever kind of birth it was. Whenever the baby's and mother's condition allow, it's recommended that mother and newborn stay in skin-to-skin contact after the birth for at least the first two hours, or until the baby has its first breastfeed.

Your baby has innate abilities that kick in after the birth if we let them. Placed tummy-down on your abdomen, thanks to their senses (above all touch and smell) and reflexes, they can reach your breast on their own. Crawling up to it, they'll smell it, touch it with their hands and then their mouth, and finally they'll be able to latch on to the breast spontaneously, with their mouth wide open, taking in the nipple and much of the areola. Find out more about the stages of breastfeeding.

Colostrum, a superfood

At this first feed, your baby will discover colostrum. This is the first milk the mammary gland produces during the last months of pregnancy and the first days after the birth, and it gives your baby all the nourishment they need in those first days. It's very thick and yellow, and mum's breasts don't feel full. This fluid is rich in calories, protein, antibodies and beta-carotene, while it's lower in fat and lactose.

Little by little, the milk will become whiter and thinner and the amount will increase (mature milk) in line with your baby's needs. Clinically, the “breast milk coming in” happens around the third day after the birth, but up to 25% of mothers notice it after 72 hours. At that point, your baby takes around 20 ml of breast milk at each feed. Bear in mind that if your baby sucks on their hands, it isn't necessarily hunger: these are the reflexes of a normal, healthy baby.

Factors that help breastfeeding get started and your milk come in

• Early skin-to-skin contact between mother and baby.
• Starting breastfeeding within the first hour after the birth.
• Frequent breastfeeding.
• A good latch (mouth to breast).
• Draining the breast properly.
• Early and frequent suckling in the first few days.

How does your baby react in the first days of breastfeeding?

Newborns usually have a phase of about two hours straight after birth when they're very awake and active. During this time, most manage their first breastfeed spontaneously during early skin-to-skin contact. They then move into a sleep phase (physiological lethargy, “recovering” from the birth) that can last 8 to 12 hours. During this phase, if they're kept skin to skin, babies will feed again when they need to.

From the first day of life, it's usual for your baby to feed often, about 8–12 times a day or more, with irregular feeds that are more frequent at night. However, some babies stay very sleepy, ask for little and feed less than they need. In these cases it helps to place them skin to skin, which helps them respond to their mother's smell and feed spontaneously. Sometimes you may need to help them wake up by undressing and dressing them again, giving them a circular massage on the soles of their feet or gently stroking their back from bottom to top. We've left you a link in case you need more information on whether or not to wake your baby.

Should I offer both breasts?

In this early stage, you should offer your baby both breasts at each feed, letting them empty one breast completely before offering the second so that they get the milk from the end of the feed, which is higher in fat and helps them grow and gain weight. It's much more important to let your baby finish the first side before offering the second, even if this means they refuse the second side at that feed. You shouldn't limit the length of feeds. It's better to let your baby feed until they show signs of being satisfied, such as coming off on their own or having relaxed arms and hands. If it's taking a long time, slip your little finger in, pressing on the palate, to avoid damaging your nipple. You don't need to wash your breasts before or after each feed, and you shouldn't use soap on your nipples as it dries them out.

Number of feeds

It's important to breastfeed on demand, whenever your baby wants and for as long as they want. That way we can be sure they'll get everything they need: sometimes food, other times warmth, affection or protection. Every baby is different and needs their own time to feed, just like us (we don't all eat at the same speed).

In the first few days, babies need to feed 8 to 14 times a day, for two main reasons: to establish breastfeeding early and to reduce the risk of low blood sugar (hypoglycaemia) in the baby. Strict feeding schedules aren't a good idea, as they inhibit natural mother–baby interaction, interfere with natural hunger cycles and make mothers anxious.

The earliest signs of hunger are sucking movements, head bobbing, sticking out the tongue, bringing hands to the mouth… This is the ideal moment to put your baby to the breast. It's not a good idea to wait until they cry, as crying is a late sign of hunger and it won't be easy for them to latch on until they've calmed down. Here's a post on crying and what each type means.

Breastfeeding technique

Most breastfeeding problems come down to breastfeeding technique: a poor position, an incorrect latch, or both.

For a good latch, it's important that your baby's whole body faces you and that, when they open their mouth, they take in a large part of the areola, especially on the lower side (where their chin is), so that when they actively move their tongue they don't hurt your nipple.

The signs of a good latch are:

• Your baby's chin touches your breast
• Your baby's mouth is wide open
• The lower lip is turned outwards (everted)
• The cheeks are rounded or flattened (not sucked in) while they suckle.
• You can see more areola above their mouth than below it.

Breastfeeding positions that will help you

Whatever position you use with your baby for feeds, there are some basic tips to bear in mind that will make it easier for your baby to latch on. There's no single right position for breastfeeding: what matters is that the mother is comfortable, the latch is good, and the baby is facing and close to the mother's body.

• As a mum, you should feel comfortable in the position. Pillows or cushions can help with this.
• Your baby's body should be in close contact with yours. When you're reclining, your baby's weight will rest on your body. This makes it easier to keep the close contact that helps trigger your baby's reflexes.
• Your baby's head should be facing the breast, in line with their body (their neck shouldn't be bent or their head turned). It's better to move the baby than to move the mother's breast.
• Your baby's chin should rest on the breast, with the nipple above the upper lip, level with the nose. That way, when your baby's rooting reflex kicks in and they latch on, their neck will be slightly extended, which helps them coordinate sucking, swallowing and breathing.
• Remember that it's better to encourage a spontaneous latch. When your baby's mouth is wide open, bring them to the breast and let your baby be the one to latch on. If your baby can't manage it, a guided latch may help.

Positions that help breastfeeding get started

Here are some positions that can help you start a happy, lasting breastfeeding journey. Find out more about breastfeeding positions

• Cradle hold:
  
  • As a mum, support your baby's neck and head with the arm and hand on the same side as the breast you're offering
• Side-lying position:
  
  • Lie on your side so that your breast rests on the mattress
  • This position is especially useful to help you rest when you have perineal pain (assisted birth, haemorrhoids…)
• Rugby (football) hold:
  
  • Support your baby's body and head with the forearm and hand on the same side as the breast you're going to offer. This leaves you a free hand to guide the latch if you need to.
  • This position is especially useful after a caesarean, for mothers with very large breasts or severe obesity, or when breastfeeding twins at the same time.
• Biological nurturing (laid-back breastfeeding):
  
  • Get comfortable in a semi-reclined position (between 15° and 65°)
  • This position is especially useful when there are latching difficulties, as it helps the newborn trigger their instinctive reflexes. You'll see your baby bob their head and move around looking for the mother's breast.

How do I break my baby's suction?

Break the suction before taking your baby off your breast. Do this by putting a clean finger into the side of your baby's mouth, between their gums. Don't take them off until you can tell they've finished. Or slip your little finger in, pressing on the palate, to avoid damaging your nipple.

Do I need to take special care of my breasts while breastfeeding?

Your breasts don't need any special care during pregnancy and breastfeeding. Daily hygiene is enough. Also, wear practical underwear with enough support to feel more comfortable.

How do I know if my baby is getting enough?

To tell whether your baby is feeding well, you can go by what the Spanish Ministry of Health's Clinical Practice Guideline on Breastfeeding says:

• How often they feed: your baby should have 8 to 12 feeds every day.
• Dirty nappies: count the nappies whose contents are at least the size of the circle you make when you touch the tips of your thumb and index finger.
  
  • Days 1–2: 1–2 wet nappies, variable meconium
  • Days 2–6: 5–8 wet nappies, at least 3 greenish stools
  • 6 days to 6 weeks: 5–6 wet nappies, at least 3 mustard-yellow stools
  • Over 6 weeks: 5–6 wet nappies; some babies poo less often but in larger, softer amounts.
• Appearance and general condition: normal skin tone, firm skin, and an active, alert baby.
• Weight gain and growth: this will be checked by your health visitor, GP or paediatrician.

Find out more about how to tell if your baby is getting enough milk by clicking here

What should I eat while breastfeeding?

Breastfeeding women don't need a special diet. The best nutrition comes from a healthy, varied diet, avoiding additives and contaminants. Only in some cases, because of illness or nutritional problems, may a doctor recommend certain supplements. Although it's been shown that the aroma of food passes into the milk and can change its smell and taste, no food is off-limits while breastfeeding. These changes in the taste of breast milk help your baby get used to different flavours, which will make it easier for them to accept solid foods later on. Only if you repeatedly notice that, after the mother has eaten a particular food, the baby shows some kind of discomfort (vomiting, diarrhoea, rashes, unsettledness or refusing the milk) may it be necessary to avoid that specific food.

Can I take medication while breastfeeding?

If you need to take medication during pregnancy or after the birth, you can ask a doctor. Remember that most medicines can be used while breastfeeding. Not all drugs pass into breast milk and, in general, in almost every situation alternatives can be offered if the chosen drug carries any risk. You can check whether a medicine is compatible with breastfeeding at www.e-lactancia.org.

Conclusion: a breastfeeding guide for the first days

Every case is unique, and you'll need to adapt these recommendations to yours. Above all, if your free and informed decision is to breastfeed your baby, you can do it. The beginning can be a little hard because of the questions this new stage raises, but little by little, with this breastfeeding guide, you'll both learn and breastfeeding will become established. And don't hesitate to lean on your midwife and breastfeeding support groups, who will be delighted to help you.

Our bottle

This guide is published by Happymami, and in this section we talk about our own product. You can see how we work.

If at any point you need or want to combine breastfeeding with bottle feeding, the Happymami bottle has a teat designed from the shape of your breast with a test. Its aim is to make it easier for your baby to accept the bottle, prevent nipple confusion and protect your breastfeeding.

In Happymami's study with 1,680 mothers, presented at the IHAN España 2024 Congress and published in Matronas Hoy (Fernández Pareja et al., 2024), 94.3 % of babies accepted the bottle and 97.4 % of mothers kept breastfeeding.

Custom-made bottle that mimics the mother's breast

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Sources

• World Health Organization (WHO). Infant and young child feeding. Fact sheet. 2026.
• Spanish Ministry of Health. Clinical Practice Guideline on Breastfeeding (Guía de Práctica Clínica sobre lactancia materna). 2017.
• Spanish Association of Paediatrics (AEP), Breastfeeding Committee. Lactancia por etapas (Breastfeeding by stages).
• APILAM. e-lactancia: compatibility of medicines and other products with breastfeeding.
• CDC. Contraindications to Breastfeeding or Feeding Expressed Breast Milk to Infants. 2025.
• Fernández Pareja M, Artenyan Markosyan L, García Galán P, Cánovas Rodríguez N, Wright S, Morán Macías T. Efectos sobre la lactancia materna usando un biberón individualizado según la morfología del pecho materno de cada madre (Effects on breastfeeding of using a bottle individualised to each mother's breast shape). Matronas Hoy. 2024;12(2):38-43.