"Is the baby sleeping through yet?" Why is everyone asking new mothers this question? And if they aren’t at a specific age, then is that something you need to worry about?

You probably don’t. In a study of 388 babies published in Pediatrics, about 38% of 6-month-olds and 28% of 12-month-olds were not yet sleeping 6 hours straight. That had no link to their development.

So, when do babies sleep through the night? Many reach a 6-hour stretch somewhere between 4 and 12 months. The exact age depends on your baby, and on what you count as "through the night."

What Does "Sleeping Through the Night" Actually Mean?

Let me put your mind at ease. There is no single definition, and the answer to "when" changes with each one.

The Three Definitions Researchers Use

• 5 hours: often midnight to 5 am
• 6 hours: any 6-hour stretch without waking you
• 8 hours: or 10 pm to 6 am, to match the family's night

Why the Definition Changes the Answer

A New Zealand study tracked 75 babies with diaries and video. The most likely age to first manage midnight to 5 am was just 2 months, and most slept 10 pm to 6 am by 5 months.

The larger Pediatrics study found many babies were still not reaching 6 or 8 hours at 12 months. Different groups and different yardsticks gave very different answers.

What to do: When someone asks if your baby sleeps through, ask yourself "by which measure?" A 7 pm to 1 am stretch is a real 6 hours, even if it does not feel like a full night. And then just ignore the question. 

When Do Babies Sleep Through the Night? What the Research Shows

The best data comes from a Canadian study of 388 mother and baby pairs. Here is how many babies were not yet sleeping through at each age.

 The same study found no link between sleeping through and mental or motor development, even when children were checked again at age 3. It also found no link with mothers' mood. Breastfed babies were more likely to still be waking.

What this means for you: If your 6-month-old is still waking at night, that is normal infant night waking, not a delay. Nearly 4 in 10 baby mamas are struggling right there with you.

Why Did My Baby Sleep 8 Hours Last Week and Wake 3 Times Last Night?

Because that is how infant sleep works. In a follow-up study, mothers logged their 6-month-old's sleep for 13 nights in a row.

• On average, babies slept 6 hours straight on about 5 of 13 nights
• They slept 8 hours straight on about 3 of 13 nights
• Only one baby in the study slept 8 hours every single night
• About 73% showed big swings from one night to the next

A Good Night Is Not a New Baseline

One great night shows your baby can do it. It does not mean they will do it every night yet.

• Look at the how the last 2 weeks went instead of just one night. 
• Expect rough patches around teething, illness, travel, and learning new skills like crawling
• Try to take a bad night in your stride as part of the pattern

Baby Sleep Milestones by Month: What Is Normal at Each Age?

Use these as normal ranges, not targets. Total sleep includes naps.

 Totals come from KidsHealth for newborns and the American Academy of Sleep Medicine from 4 months up. Stretch lengths reflect the studies above and vary a lot from baby to baby.

What to do: If your baby's total sleep lands in range and they are growing well, a short longest stretch is usually not a problem to fix.

What Can You Actually Control?

You cannot speed up your baby's body clock. You can shape the conditions around it.

A Short, Consistent Bedtime Routine

In a study of 405 young children, babies 7 to 18 months with sleep problems got a simple 3-step routine every night for 2 weeks. They woke less often and for shorter spells. Their longest stretch grew from about 6.9 to 8.5 hours, and mothers' mood improved too.

• Bath, gentle massage, then a quiet cuddle or song
• Same steps, same order, about the same time each night
• Keep it short: 20 to 30 minutes is plenty

The Sleep Space

Sometimes babies have trouble settling if their sleep space isn’t comfortable or feels different. 

Surface and Sheet

Safe to Sleep recommends a firm, flat surface covered only by a fitted sheet, with nothing else in the sleep area. A sheet that stays tight on the exact mattress you own keeps that setup safe all night. If you are choosing fabric, here is how jersey, muslin, and bamboo sheets compare.

Temperature and Light

• Dress your baby in a wearable blanket instead of loose blankets, and avoid overheating, per Safe to Sleep
• Pick sleepwear weight with a simple TOG rating guide
• Keep nights dim and quiet, and days bright and lively, so your baby learns night is for sleep, as the NHS suggests

Night Feeds

As babies grow, they need fewer night feeds. The NHS notes some babies sleep 5 to 8 hours or longer, but not all.

What to do: Ask your pediatrician when it is okay to drop a night feed, based on your baby's weight gain, not on age alone.

Is Sleep Training Safe? What the Evidence Supports (and What It Doesn't)

You will hear strong opinions on both sides. Here is what the trials actually found.

What the Evidence Supports

• In a randomized trial of 43 babies aged 6 to 16 months, timed check-ins and a later, gradually adjusted bedtime both helped babies fall asleep faster. Timed check-ins also cut night wakings.
• That trial found no rise in the stress hormone cortisol and no difference in attachment a year later.
• A 5-year follow-up of 326 children found no long-term harm from gentle methods like controlled comforting or sitting by the crib.

What It Does Not Show

• The 5-year study found no long-term benefit either. By age 6, both groups slept about the same.
• The trials studied babies 6 months and older, not newborns.
• Some trials were small, and stress was measured with saliva tests.

What to do: If you want to try it, the evidence says it is unlikely to cause harm. If you would rather not, the Pennestri data says your baby's development will not suffer. Both are reasonable choices.

When Is Night Waking a Reason to Call Your Pediatrician?

Most night waking is normal. Call your pediatrician if you notice:

• Snoring most nights, gasping, or pauses in breathing, which Duke Health lists as signs of a sleep breathing problem
• Crying that seems like pain, or arching during feeds
• Poor weight gain or trouble feeding
• A sudden change in sleep that lasts more than 2 weeks with no clear cause

If your baby turns blue or struggles to breathe, call 911.

Your Baby's Timeline Is the Right One

There is no deadline for sleeping through the night. Some babies get there at 2 months. Some are still working on it at 18 months. Both are normal.

Focus on what you control: a calm routine, a safe sleep space, and patience with the bad weeks. The long nights do end, even when it feels like they won't. You can also try these tips to try and get your baby to sleep in 40 seconds. 

One thing you can set up tonight is the sleep surface. Joey & Joan fitted sheets are 100% jersey cotton, OEKO-TEX certified, and sized to specific bassinet, crib, mini crib, and playard models, so they stay snug on the mattress you already own. Find the sheet that fits yours.

Frequently Asked Questions

How many hours should a baby sleep at night?

Most babies sleep 9 to 12 hours at night, usually with a feed in between, plus 2 to 3 naps, per the NHS.

Should I wake my newborn to feed at night?

Yes, every 3 to 4 hours until your baby shows good weight gain, usually within the first couple of weeks, per KidsHealth. After that, your pediatrician can tell you when longer stretches are fine.

Does rice cereal in a bottle help babies sleep longer?

No. A trial of 106 babies found bedtime cereal made no difference to sleeping through, and it is not recommended.

Is it okay to rock or cuddle my newborn to sleep?

Yes. KidsHealth says rocking, cuddling, and singing to a fussy newborn is fine.

When should my baby move from the bassinet to the crib?

Usually when they reach the bassinet's weight limit or start rolling or pushing up. Here is more on how long a baby can sleep in a bassinet.

Sources

1. Uninterrupted Infant Sleep, Development, and Maternal Mood – Pediatrics study of 388 babies on how many sleep through at 6 and 12 months, and links to development.
2. Sleeping Through the Night or Through the Nights? – Sleep Medicine study tracking night-to-night sleep in 6-month-olds over 13 nights.
3. Sleeping Through the Night: The Consolidation of Self-regulated Sleep Across the First Year of Life – Pediatrics study comparing three definitions of sleeping through across the first year.
4. Sleep and Your Newborn – Nemours KidsHealth guide to newborn sleep totals and night feeds.
5. Recommended Amount of Sleep for Pediatric Populations – American Academy of Sleep Medicine consensus on daily sleep needs by age.
6. A Nightly Bedtime Routine: Impact on Sleep in Young Children and Maternal Mood – Sleep journal study on how a 3-step routine changed night waking.
7. Safe to Sleep – NICHD campaign guidance on safe infant sleep surfaces and bedding.
8. Helping Your Baby to Sleep – NHS advice on day and night routines and night feeds.
9. Behavioral Interventions for Infant Sleep Problems: A Randomized Controlled Trial – Pediatrics trial of timed check-ins and bedtime fading, including stress and attachment.
10. Five-Year Follow-up of Harms and Benefits of Behavioral Infant Sleep Intervention – Pediatrics follow-up of 326 children at age 6 after infant sleep training.
11. Does Your Child Snore? When to See a Doctor – Duke Health pediatric ENT guidance on snoring and sleep breathing problems.
12. Healthier Together: Sleep – NHS guidance on how much babies sleep at night and in naps.
13. Infant Sleep and Bedtime Cereal – Randomized trial of 106 infants on cereal in the bedtime bottle.