Night wakings around 4 months

Somewhere around 4 months, many parents notice that nights get harder. A baby who had started to sleep in longer stretches suddenly wakes more often, or naps get shorter. This is often called the "4-month sleep regression". It is common, but not every baby goes through it, and the timing varies — for some it starts closer to 3 months, for others nearer 5.

What is changing

In the newborn weeks, sleep does not yet follow a regular pattern. Paediatricians note that a regular rhythm of sleep cycles only appears at around 4 months. As the brain matures, a baby's sleep starts to look more like an adult's: it moves through lighter and deeper stages in repeating cycles, and at the end of each cycle the baby passes through a light phase and may stir or wake briefly.

Sleep is not going backwards. It is maturing. The difference is that a baby who needs help to fall asleep at the start of the night may now look for the same help at each of those brief wakings.

How long it lasts

Because this is a lasting change in how your baby sleeps rather than a passing phase, there is no fixed end date. For most families the disruption eases over a few days to a few weeks, as the baby gets used to the new pattern.

What is normal at this age

• Night sleep. At 3–6 months, babies typically sleep around 10–12 hours at night, and about 13½–15 hours in 24 hours with naps.
• Night wakings. Waking once or twice a night for a feed or comfort is common at this age, and some babies wake more often.
• One longer stretch. Many 4-month-olds manage one stretch of 5–6 hours at night. Breastfed babies often wake more.
• Night feeds. Needs differ. Many formula-fed babies no longer need a middle-of-the-night feed somewhere between 2 and 4 months, while breastfed babies may still feed at night for longer. Your doctor or health visitor can tell you what is right for your baby.

What helps

• Put your baby down drowsy, not fully asleep. From around 4 months, paediatricians suggest laying babies down when they are sleepy but still awake. It gives them the chance to practise falling asleep in their own bed, which makes it easier to drift off again between cycles.
• Keep a short, predictable bedtime routine. Twenty to thirty minutes of the same calm steps every evening helps signal that night is coming.
• Make day and night look different. Clear routines when awake and when asleep help your baby's body clock settle towards night-time sleep.
• Watch for tired signs. Fussiness or rubbing eyes are cues that it is time to sleep. At this age a wake window of about 1½–2 hours is typical.
• Extra comfort for a while is fine. On hard nights you may need to soothe more than usual. That is normal. Consistent, calm sleep habits help this phase settle. Whatever you do, keep to safe sleep: on the back, in your baby's own cot.

When to talk to a doctor

Talk to your doctor or health visitor soon if your child:

• snores often, seems to struggle to breathe at night, or is very sleepy during the day;
• is not gaining weight as expected, or has lost their appetite;
• has sleep problems you are finding hard to manage.

If you are worried and not sure what to do, it is always fine to ask. If night wakings suddenly come with a fever, poor feeding or a baby who seems unwell, see a doctor rather than putting it down to the regression.

If your baby is under 3 months old with a temperature of 38 °C (100.4 °F) or higher, or 3–6 months old with 39 °C (102.2 °F) or higher, call your doctor straight away. If you cannot reach a doctor, call your local emergency number.

Call your local emergency number now if your baby:

• stops breathing for more than 20 seconds;
• is breathing very fast or with great effort — grunting, or sucking their tummy in with each breath;
• has blue, grey, pale or blotchy skin, lips or tongue;
• is very hard to wake, or will not wake up;
• is floppy, or is not feeding;
• has a seizure (fit), or a rash that does not fade when you press a glass against it.

Sources

• American Academy of Pediatrics, HealthyChildren.org — Getting your baby to sleep
• American Academy of Pediatrics, HealthyChildren.org — Amount and schedule of formula feedings
• American Academy of Pediatrics, HealthyChildren.org — Sleep apnea: signs to watch for
• American Academy of Pediatrics, HealthyChildren.org — When to call the pediatrician: fever
• NHS — Is your baby or toddler seriously ill?
• KidsHealth (Nemours) — Your child's checkup: 4 months
• KidsHealth (Nemours) — Failure to thrive: when to see a doctor
• Cleveland Clinic — Sleep in your baby's first year
• Sleep Foundation (medically reviewed) — 4-month sleep regression
• Taking Cara Babies — The 4 month sleep regression