Why Is My Baby Not Sleeping at Night? Causes by Age

Why Is My Baby Not Sleeping at Night? Causes by Age (0-2 Years)

It was 2:47 AM when I finally stopped pretending this was a phase.

My son had woken up for the fourth time that night, and I was standing in the dark rocking him, doing the maths on how many hours of sleep I’d had that week. Everyone had an explanation. Teething, my mother said. Growth spurt, said my sister. He’s just a bad sleeper; said someone in a mom group I’ve since muted.

If you’re awake right now searching “why is my baby not sleeping at night,” none of those one-word answers probably feel like enough. They weren’t for me either. The truth is the cause changes as your baby grows, what wakes a newborn is rarely what wakes a one-year-old.

Why Sleep Falls Apart — The Short Version: –

Baby sleep isn’t broken by one problem. It’s usually a stack of small one’s development, environment, hunger, and habit and the mix changes almost every few months. The fastest way to fix it is figuring out which one you’re actually dealing with, instead of trying every solution at once.

• Newborns wake often because their sleep cycles are short and their stomachs are small this is biology, not a problem to solve.
• Sleep regressions around 4, 8-10, and 18 months are tied to real developmental leaps, not something you caused.
• A room that’s too warm, too bright, or too noisy can undo an otherwise good routine.
• An overtired baby fights sleep harder than a well-rested one the fix is often an earlier bedtime, not a later one. This video will help you out  Why Newborns Wake So Often.

0-3 Months: Newborn Sleep Is Supposed to Be Fragmented: –

This is the age where “not sleeping” is usually normal, even when it doesn’t feel that way at 3 AM.

• Newborn sleep cycles run about 45-60 minutes, roughly half the length of an adult’s frequent waking is built in, not a fault in your routine.
• Small stomachs mean babies genuinely need to feed every 2-3 hours, including overnight, for the first couple of months.
• Day-night confusion is common in the first few weeks-exposing baby to bright natural light in the morning and keeping nights dim helps reset the body clock faster.
• The startle (Moro) reflex wakes many newborns from light sleep-swaddling snugly (arms in, hips loose) often helps.

If your newborn is waking every 2-3 hours, that’s not a sleep problem to fix – it’s what this age looks like. Sleep gradually consolidates on its own over the next few months.

4-8 Months: The Regression Everyone Warns You About: –

This is usually where things that were working suddenly stop working, almost overnight.

• Around 4 months, your baby’s sleep cycles mature to look more like an adult’s-with lighter stages in between, it becomes easier to wake up and harder to fall back asleep alone.
• Teething discomfort often starts in this window and can cause real, not imagined, night waking.
• Rolling and other new physical skills tend to get “practised” in the crib at 2 AM, even in a baby’s sleep.
• Growth spurts around 3, 6, and 9 months can temporarily increase night hunger even in babies who were previously sleeping longer stretches.

This is also the age most parents start intentional sleep training, once a baby is developmentally ready to learn to fall back asleep independently.

9-2 Months: Separation Anxiety and the Second Regression: –

Just as things stabilise, a second wave hits — this time, it’s emotional as much as physical.

• Separation anxiety typically peaks between 8-10 months baby waking and needing to see you isn’t manipulation; it’s a real developmental stage.
• Pulling up to stand in the crib is a new skill many babies can’t resist practising at night, even half-asleep.
• Naps often start shifting during this window as baby transitions from 3 naps to 2 a mistimed nap schedule shows up as harder nights.
• More teeth are usually coming in, and molars later in this window tend to hurt more than the first ones did. Watch this video which is on The 8–10 Month Sleep Regression, Explained .

1-2 Years: Nap Transitions, Fears, and Testing Limits: –

Toddler sleep struggles look different less about biology, more about a fast-developing mind.

• The drop from 2 naps to 1 nap usually happens between 12-18 months and briefly disrupts night sleep while the body adjusts.
• Imagination is developing, and mild fears of the dark or being alone can genuinely start around 18 months.
• Molars coming in around 13–19 months and again near 2 years are a common, under-blamed cause of a sudden sleep dip.
• Toddlers are also testing boundaries at bedtime the same way they do everywhere else a consistent, calm routine matters more here than at any earlier stage.

Before You Blame a Regression Rule These Out First: –

Not every bad night is developmental. A few environmental and routine factors are worth checking at any age.

• Room temperature: ideally around 20–22°C (68–72°F); too warm is a more common problem than too cold in most Indian homes.
• Overtiredness:  an overtired baby often wakes more, not less; watch for the first yawn instead of waiting for meltdown-level tiredness.
• Illness: a cold, ear infection, or reflux flare can disrupt sleep for days and won’t respond to any routine fix until it clears.
• Recent changes: travel, a new caregiver, starting daycare, or moving rooms can unsettle sleep for 1–2 weeks on its own.

A Quick Safety Reminder: –

• Always place baby on their back to sleep, on a firm flat surface, for every sleep until at least 12 months.
• Keep the crib clear no loose blankets, pillows, or soft toys for babies under 12 months.
• Room-sharing (not bed-sharing) for the first 6 months is the current safe-sleep recommendation.

Sleep Trouble Quick Reference: –

• 0-3 months: frequent waking is normal short sleep cycles and small stomachs, not a problem to fix.
• 4-8 months: regression, teething, or growth spurts often when sleep training becomes possible.
• 9-12 months: separation anxiety and nap transitions are the usual culprits.
• 1-2 years: nap drop, new fears, and molars routine and consistency matter most.

When to See a Doctor Instead of Waiting It Out: –

Most sleep disruption is developmental and resolves on its own within 1-3 weeks. Check in with your paediatrician if waking is paired with fever, poor weight gain, laboured or noisy breathing during sleep, or if a previously good sleeper suddenly can’t settle at all for more than 2 weeks that pattern is worth ruling out medically rather than waiting on a routine fix.

If You’ve Ruled Out the Basics and Still Aren’t Sleeping: –

MyDvija’s Sweet Sleep – Sleep Training & Day Routine Course gives you a 21-day, cue-based plan built for babies 0–2 years, including how to handle regressions as they come up.

For ongoing support from 3 months postpartum through your baby’s third year sleep, nutrition, and development together the Care Club for Mom & Baby covers all of it in one programme.

Stuck on one specific issue — early waking, a nap transition, a regression that won’t end a 30-minute consultation with Shrreya Shah troubleshoots your exact situation.

This video will help you out to take a look and understand A Real 21-Day Sleep Training Walkthrough.

Also, Worth Reading

• Baby Sleep Training Techniques: A Guide for Tired Parents
• Sleep Training Without Crying It Out: Gentle Methods That Actually Work
• Nap Schedules by Age — A No-Nonsense Guide for Moms

There will be nights that break you a little. The 2 AM ones where you’ve tried everything and nothing is working and you start wondering what you’re doing wrong.

You’re probably not doing anything wrong. Your baby is just growing, and growing is loud at night.

Figure out which stage you’re in, fix what’s actually fixable, and let the rest be what it is a phase, not a verdict on your parenting.