"When will my baby sleep through the night?" It's the question every new parent asks within the first week. The answer is more complicated โ and more reassuring โ than most people expect.
What "Sleeping Through" Actually Means
Medically, "sleeping through the night" means a stretch of 5โ6 hours โ not 8โ10 like adults assume. So a baby sleeping from 11pm to 4am is technically sleeping through the night, even if that feels far from restful for you.
Realistic Timeline by Age
0โ3 months: Biologically impossible to sleep through. Newborns need feeding every 2โ3 hours. Their stomachs are too small. Anyone who tells you their newborn sleeps 8 hours is either very lucky, misremembering, or not waking up when they should.
4โ6 months: Some babies begin naturally consolidating sleep into 4โ6 hour stretches. This is when sleep training, if you choose it, becomes developmentally appropriate. Around 50% of babies achieve a 5-hour stretch by 5 months.
6โ9 months: The majority of babies are capable of sleeping 6โ8 hours without feeding. Whether they do depends largely on what habits have been established at bedtime.
9โ12 months: By 9 months, most healthy, well-fed babies can sleep 8โ10 hours. If yours isn't, the cause is almost always a sleep association โ needing feeding, rocking, or a dummy to fall back asleep at each cycle.
12+ months: Expect regressions. Teething, illness, developmental leaps, and transitions all temporarily disrupt sleep that was previously solid. This is normal, not a step backwards.
The Single Biggest Factor
More than age, more than feeding, the single biggest predictor of whether a baby sleeps through the night is how they fall asleep at bedtime. A baby who falls asleep feeding will need feeding to fall back asleep at every cycle boundary โ typically every 45โ90 minutes. A baby who falls asleep independently will reconnect their sleep cycles on their own.
This is the whole basis of "drowsy but awake" โ put the baby down before they're fully asleep, so they learn to complete the process themselves.
It's Not a Milestone You Can Force
Some babies are genuinely not developmentally ready regardless of what you do. If yours is under 4 months and waking frequently, this is almost certainly biology, not a problem to solve. Be patient with yourself and with them.