My baby was sleeping through the night at three months but then four months hit and it all went to south! What happened?

“My baby was sleeping through the night (or chunks of a few hours at least) at three months but then four months hit and it all went to pot and now at five months, they fight sleep to the death and wake so often, any clue what the hell is going on?”

There is a huge amount of growth and development that happens around four months, which understandably affects many babies’ sleep.

These changes at four months can be really rough for baby - which makes it really rough for the caregivers, and we get what is commonly known as the “four month sleep regression.” But it’s really a “progression”. Your baby is learning new skills, and developing new parts of her brain.

It is totally normal and the best way possible to help your baby through it, is with lots of touch and nursing and closeness. That waking isn’t a habit and nothing you do will create a habit - it’s a biological need, fueled by major brain changes, and real, big, scary emotions and physical feelings for bub.

If baby is soothed by partner and a bottle sometimes you can definitely do that -but basically, just getting through it is the way through it.

And it WILL pass, without any intervention.

Sleep training rhetoric is great at creating fear. Fear that this means you’ll need to sleep train, fear that if you nurse and rock baby through it you’re creating “sleep props” or associations, fear that this phase won’t pass and your baby’s sleep is broken forevermore - unless you use their program which is guaranteed to “fix” everything. We hear these false assertions so much and they’re insidious. They’re not based on any research. They seem to make common sense so that we let them creep in to our mental map, but this really is not the way it works. 

Some babies fly through that big bump in a week or two. Some take a month or two. Some wake that much for years. Likely, your bub will get through it relatively quickly but as it could last longer, finding ways for you to get enough sleep is worth doing right away so you don’t get to that desperate place where you simply “can’t anymore”. Can your partner take her when she wakes so you can sleep in? Or the same in the evening while you go to bed early? Can you modify your sleep environment so you sleep as many minutes of baby’s stretches of sleep as possible too? Can you nap during the day with her?


My son didn’t get longer than a 40 minute stretch for 2 years, and nothing but nursing helped - but we managed just fine once I sounded the alarm and admitted it sucked and that I needed help. We found changes to life that made it all tolerable and I got enough sleep to be happy. It really is possible. In the short term, stop counting wakes or turning on lights or looking at your phone. This can massively decrease the disruption of each wake. Dropping all other obligations for a bit like cooking, cleaning and social calls to the absolute minimum helps the helpless overwhelmed tired feeling. Getting out in nature and sunlight during the day helps feel more rested and grounded.

Help – My 4-5 Month Old Is Sleeping Like a Newborn Again (AKA ‘The 4-5 month old babies from hell’)

The Myth Of Baby Sleep Regressions

4 Month Monsters! 6 Ways Babies Change + Survival Tips

16 Week Old Baby | Your Baby Week By Week

What is Normal Infant Sleep? (Part I)

“Sleep Regressions”: Why It’s Not Actually a Regression

Helping Baby Sleep: Does Extinction Sleep Training Improve Baby’s Sleep?

The Myth of Baby Sleep Regressions