Days one and two: colostrum

Your breasts are not empty at birth. The NHS describes the fluid produced in the first days as colostrum: "It's thick and usually a golden yellow colour." The HSE's description of what it does is the useful one — it is made in exactly the amounts a newborn stomach can hold, it clears meconium, and it reduces jaundice.

Volumes are tiny and that is the design. A first feed may be a few millilitres. This is why expressed colostrum is measured in a syringe rather than a bottle, and why "I only got a few drops" is not evidence of a problem in the first 48 hours.

Get the first feed as early as you can. The HSE's guidance on a baby's first feed centres on skin-to-skin and letting your baby find the breast in their own time, which many newborns will do within the first hour if left undisturbed on your chest.

How often, and why it feels relentless

The NHS gives the working number: "As a very rough guide, your baby should feed at least 8 to 12 times, or more, every 24 hours during the first few weeks." It also notes babies may want to feed "quite often, perhaps every hour to begin with."

Feeds are not evenly spaced. A newborn may feed six times between 8pm and midnight and then sleep a four-hour stretch. Counting the 24-hour total rather than the gaps is the only way to make sense of it.

Frequency in week one is what sets supply for the months after it. Every effective feed removes milk and signals your body to make more. That is why "topping up so you can rest" tends to reduce supply, and why waking a very sleepy baby to feed is sometimes advised in the first days.

Day three: the milk comes in

Around day two to four, colostrum transitions to larger volumes of mature milk. Your breasts may become noticeably fuller, firmer, warmer and heavier. This can arrive alongside a sharp emotional dip — often called the baby blues — which is hormonal, extremely common, and usually passes within a few days.

Very full breasts can make latching harder, because the areola becomes firm and your baby cannot draw enough of it in. The fix is to soften the areola first with a little hand expression or reverse pressure softening, then latch. Feeding frequently is what prevents this from tipping into engorgement.

If you had a caesarean, expect this to run perhaps a day later. That is normal and not a signal of low supply.

What a good feed looks like

La Leche League GB's list of signs of effective feeding in the early days is the practical checklist. Your baby's cheeks stay rounded rather than sucked in, you can hear swallowing, the chin is pressed into the breast, and the pattern moves from quick shallow sucks to slow deep ones with pauses.

The NHS describes the mechanism behind that shift: "Your baby's sucking causes muscles in your breasts to squeeze milk towards your nipples. This is called the let-down reflex." Some people feel a strong tingling, some feel nothing, and neither predicts how much milk there is. The reliable sign is watching your baby's sucking change to deep rhythmic swallows.

Your nipple should come out of your baby's mouth the same shape it went in. A flattened, creased or wedge-shaped nipple means the latch was shallow.

Nappies: the measurement you actually have

Because you cannot see how much has gone in, output is the proxy. The pattern changes daily in week one: wet nappies increase from one on day one towards six or more heavy wet nappies a day by the end of the first week, and stools change from black meconium through greenish-brown changing stools around days three to four to yellow, loose, seedy breastfed stools thereafter.

Your midwife or public health nurse will be checking these against the specific chart your health service uses, and the numbers vary slightly between countries, so use theirs. What matters is the direction: nappies should be increasing, and stools should be changing colour by day four.

Weight, and the number that gets misread

Newborns lose weight in the first days before regaining it. Your midwife will weigh your baby and calculate the loss as a percentage of birth weight, and there is a threshold at which feeding is formally assessed. Most babies are back to birth weight within about two weeks.

Weight is one measure among several. A baby with good nappy output, active feeding and normal alertness is a different picture from a sleepy baby with few wet nappies, even at the same percentage.

Cluster feeding and the evening stretch

Late in the first week many babies begin a long evening run of feeding, often with fussing between feeds. UNICEF UK Baby Friendly's parent-facing guide to the first week with a breastfeeding newborn names this as normal, and it is one of the most common reasons people introduce formula in week one believing their supply has failed.

It is worth knowing in advance that this will probably happen, and that it usually does not mean what it feels like it means.

Your body in week one

Afterpains during feeds are normal, especially with second and later babies. Nipple tenderness at the start of a feed is common in the early days and should settle within about a week. Pain that lasts through the whole feed, or that is still there after the first week, is not something to endure — it is the signal that positioning needs correcting.

Eat and drink when you can, and keep water within reach of wherever you feed. Thirst during let-down is real.

When to ask for help

Ask your midwife, health visitor, public health nurse or a breastfeeding specialist promptly if:

Your baby will not attach, or slips off repeatedly.
Feeding hurts throughout the feed, or your nipples crack or bleed.
Wet nappies are not increasing, or stools are still dark by day four.
Your baby is consistently feeding fewer than eight times in 24 hours, or is too sleepy to wake for feeds.
Your baby has not started regaining weight by the end of the first week.

Seek urgent medical advice if your baby is difficult to rouse, is not feeding at all, has a dry mouth and no wet nappies for many hours, or looks increasingly yellow. The NHS advice is unambiguous: speak to a midwife or health visitor if you are worried about breastfeeding or think your baby is not getting enough milk.

Where to get real help

In the UK the National Breastfeeding Helpline is 0300 100 0212, run by the Breastfeeding Network and the Association of Breastfeeding Mothers, and open every day of the year. La Leche League GB runs local groups and a helpline. In Ireland the HSE offers an "Ask our breastfeeding expert" live chat and email service, Monday to Friday. Having someone watch a whole feed in week one is worth more than anything you can read.

The First Week of Breastfeeding