Your baby at three weeks: growth spurts, cluster feeding and the witching hour

Newborn · Development · Reviewed 20 June 2026 · All articles

Three weeks in and the haze of the very early newborn days is beginning to lift, just a little. Your baby is starting to look more alert, may be holding your gaze for a second or two, and is eating more than ever before. It can also feel like things are suddenly harder: more fussiness in the evenings, feeds that seem to last for hours, and nights that refuse to lengthen. All of this is normal and temporary. This guide walks through what is happening developmentally at three weeks so you understand the why behind what you are seeing.

Development at a glance

• Typical weight: birth weight regained by now (most babies), gaining approximately 150 to 200 g per week
• Typical length: around 50 to 53 cm, though there is wide natural variation
• Feeding: 8 to 12 feeds in 24 hours is still the norm; cluster feeding in the evenings is very common
• Sleep: 14 to 17 hours across 24 hours in short stretches of 2 to 4 hours
• Alertness: wakeful periods are becoming slightly longer and more predictable
• Social: may turn toward a familiar voice; brief eye contact emerging
• Health watch: colic can begin around 2 to 3 weeks and typically peaks at 6 weeks

Every baby is different. These figures represent what is typical for most babies, not a test your baby must pass. If you have concerns about growth or feeding, your health visitor or paediatrician is the right person to ask.

Physical development at three weeks

By three weeks most babies have regained their birth weight and are now climbing steadily above it. The rule of thumb used by most health professionals is an average gain of 150 to 200 grams per week during the first few months, though week-to-week variation is normal. What matters more than any single weigh-in is the general upward trend on the growth chart.

Physically, your baby is still very much in the newborn stage. Movements are jerky and reflexive. The head still needs full support. Limbs are often curled in the flexed position they held in the womb. The skin, which may have been peely or blotchy in week one, is usually settling into a smoother texture by now, though baby acne (tiny white or red spots across the nose and cheeks) can appear around two to three weeks and is entirely harmless.

One thing you may notice is that your baby is beginning to have slightly longer wakeful periods. In the first two weeks many babies were awake mainly to feed and then dropped straight back to sleep. At three weeks you may see a window of 20 to 45 minutes where your baby is genuinely alert, looking around, and interested in faces. These wakeful windows are short and unpredictable at this stage, but they are the early foundation of the baby's developing circadian rhythm.

Feeding: growth spurts and cluster feeding

The three-week growth spurt is one of the most talked-about moments in the newborn period, and for good reason. Growth spurts are periods of increased appetite, fussiness, and frequent feeding that correspond with the baby putting on length and weight. They typically occur around 10 days, 3 weeks, 6 weeks, 3 months and 6 months, though not all babies follow this timetable neatly.

During a growth spurt your baby may want to feed far more often than usual, sometimes seeming hungry again just 30 to 40 minutes after finishing a full feed. This is normal and not a sign that your milk supply is insufficient. In fact, the frequent feeding is precisely what stimulates more milk production. The spurt usually lasts two to four days and then settles.

What is cluster feeding?

Cluster feeding is when a baby feeds many times in a short period, often with only brief breaks between. It is most common in the late afternoon and evening, typically between 5pm and midnight. During a cluster feed your baby may latch, feed briefly, come off, fuss, latch again, and repeat for two to four hours without seeming satisfied.

This can be exhausting and it is completely understandable to wonder whether something is wrong. In most cases cluster feeding is a normal behaviour that serves two purposes: it helps build milk supply, and it loads the baby up with calories in preparation for a slightly longer stretch of sleep later in the night. Feeding on demand during cluster periods is the recommended approach for breastfed babies. Formula-fed babies may also cluster feed, and it is safe to offer extra feeds during this period within the guidance of your midwife or health visitor.

A few things that can help during cluster feeding: make a comfortable nest on the sofa with snacks, water and something to watch; have a partner or support person take the baby between feeds so you can rest; and remind yourself that the phase is temporary.

Sleep at three weeks

Three weeks is still firmly the newborn sleep territory, which means short stretches, frequent night waking, and no consolidated nighttime sleep. Most babies this age sleep between 14 and 17 hours in total across 24 hours, but that sleep is distributed in 2 to 4 hour chunks around the clock. Some babies begin to show a slightly longer stretch of 4 to 5 hours once in the night; many do not yet.

At this stage the goal is not sleep training or any attempt to extend sleep. The baby's stomach is small and genuinely needs frequent refuelling. Night feeds are normal and necessary. Focusing on safe sleep practices, such as placing the baby on their back on a firm flat surface, keeping the sleep space clear of soft objects and loose bedding, and room-sharing without bed-sharing, remains the priority.

If you are exhausted from night feeds, sleep when the baby sleeps where you safely can, and accept help from any trusted adult who can take a stretch so you get two to three consecutive hours. Sleep deprivation is cumulative and caring for yourself is part of caring for your baby.

Health, senses and the witching hour

At three weeks your baby's senses are developing rapidly. Vision is still best at close range of about 20 to 30 cm (roughly the distance from your breast or the crook of your arm to your face). Babies at this age show a preference for high-contrast patterns and, above all, human faces. You may catch your baby fixing on your eyes for a second or two before looking away. This is the earliest form of social engagement and it is worth cherishing.

Hearing is fully functional from birth and your baby already recognises your voice. You may notice your baby turning toward the sound of your voice or showing a calming response when you speak or sing. Talking to your baby during nappy changes, feeds and wakeful periods is never too early.

The witching hour

The witching hour is the informal name for a period of intense fussiness and inconsolable crying that many babies show in the late afternoon and evening, typically between around 6pm and midnight. The baby may cry, pull up their legs, pass wind, and be very difficult to settle even after a full feed. The witching hour is not the same as colic (though the two often overlap), and it is not caused by anything the parent is doing wrong.

The exact mechanism behind the witching hour is not fully understood, but factors that likely contribute include an immature nervous system that gets overstimulated by a day's worth of input, lower breast milk volume or fat content in the late afternoon for some breastfeeding parents, and the natural cortisol patterns of a newborn that have not yet settled into a day-night rhythm.

Strategies that help some families: feeding on demand throughout the witching window, skin-to-skin contact, gentle movement such as rocking or swaying, white noise, going for a walk in a carrier or pram, and handing the baby to a second caregiver for 20 minutes while you step away briefly. No single strategy works for every baby. The witching hour typically peaks around four to six weeks and then gradually eases over the following weeks.

Colic

Colic is defined as crying for more than three hours a day, on more than three days in a week, for more than three weeks, in an otherwise healthy baby. It typically begins around two to three weeks of age, peaks at six weeks, and resolves by three to four months. The cause is not fully established. Current evidence does not support the routine use of gripe water, simethicone drops or other over-the-counter remedies, though some parents find them helpful. If you suspect colic, speaking to your doctor or health visitor is worthwhile to rule out other causes and to get support.

It is important to note that colic and cluster feeding can look very similar from the outside. A baby who is feeding frequently, crying in the evenings and difficult to settle may simply be cluster feeding through a growth spurt rather than experiencing colic. If your baby is gaining weight, having regular wet and dirty nappies, and is generally settled between crying episodes, feeding-related behaviour is the more likely explanation.

What comes next: approaching week four

Week four marks the approach of the end of the official newborn stage (usually defined as the first four weeks). While you will not notice a sudden change on day 28, the trend over the coming weeks is genuinely encouraging.

Most babies begin to show their first true social smiles around four to six weeks. Wakeful periods gradually lengthen. Cluster feeding and the witching hour typically begin to ease around six to eight weeks. Night stretches, while still variable, often begin to extend slightly as the baby's stomach capacity grows and their circadian rhythm matures.

You are also continuing to recover from birth and adjusting to life with a newborn. If you are feeling persistently low, anxious, overwhelmed or unable to bond with your baby, please speak to your doctor or midwife. Postnatal depression and postnatal anxiety affect many new parents and are treatable. Asking for help is a strength, not a failure.

Frequently asked questions

Is it normal for a three-week-old to feed every hour in the evening?

Yes. Cluster feeding, where a baby feeds very frequently for several hours, is completely normal at three weeks and is especially common between 5pm and midnight. It is one of the main ways babies drive up your milk supply during a growth spurt. Offer the breast or bottle on demand and rest as much as you can between feeds.

How much weight should a three-week-old be gaining?

Most babies gain around 150 to 200 grams per week during the newborn period when feeding is going well. Your midwife or health visitor will plot weight on a centile chart at each check. A single weigh-in means less than the overall trend, so try not to fixate on one number.

When does the witching hour end?

The witching hour, which is the period of intense fussiness and cluster feeding that tends to happen in the late afternoon and evening, typically peaks around four to six weeks and then gradually eases. Most families notice a clear improvement by around three months as the baby's digestive system matures and circadian rhythms develop.

Could my three-week-old have colic?

Colic, defined as crying for more than three hours a day on more than three days a week, can begin around two to three weeks and typically peaks at six weeks before resolving by three to four months. The exact cause is not fully understood. If your baby is otherwise feeding, gaining weight, and having regular wet and dirty nappies, colic is usually the explanation. Always speak to your doctor if you are unsure or if your baby seems unwell.