You finally had a routine. Your baby was settling well, sleeping for longer stretches, and you were starting to feel human again. Then, seemingly out of nowhere, everything fell apart.
If this sounds familiar, there's a good chance you're in the middle of a sleep regression — and understanding what's happening can make an enormous difference to how you cope with it.
What Is a Sleep Regression?
A sleep regression is a period — typically lasting two to six weeks — when a baby who has been sleeping relatively well suddenly begins waking more frequently, fighting sleep, or taking shorter naps. It can feel like going backwards, but what's actually happening is the opposite: your baby is going through a significant developmental leap, and their brain is working overtime.
Sleep regressions are a completely normal part of infant development. They are not a sign that you've done something wrong, that your routine has failed, or that your baby is a poor sleeper. They are temporary — even when they don't feel it.
When Do Sleep Regressions Happen?
The most commonly recognised sleep regressions occur at the following ages. These are approximate — every baby is different, and not every baby will experience every regression in the same way.
The 4-month regression This is widely considered the most significant and disruptive regression, and unlike later ones, it reflects a permanent change in how your baby's sleep cycles work. Around this age, babies transition from predominantly deep sleep to a more adult-like sleep pattern with lighter cycles — meaning they now partially wake between sleep cycles, which was previously happening seamlessly.
What this means in practice: your baby may wake every 45-60 minutes overnight rather than sleeping in longer stretches. They may need more support to resettle than before.
What helps: consistency is your biggest ally here. Maintaining a predictable bedtime routine — bath, feed, wind-down, sleep — helps signal to your baby that sleep is coming. If you haven't yet introduced a firm bedtime routine, now is a good time to start.
The 8-10 month regression At this stage, your baby is going through rapid cognitive and physical development — learning to crawl, pull to stand, and developing a much stronger understanding of object permanence (the awareness that you still exist even when they can't see you). This is why separation anxiety often peaks around this time.
Overnight, this can translate into more frequent waking and greater difficulty settling without you present.
What helps: a consistent, reassuring bedtime routine. Some parents find a gradual withdrawal approach helpful at this stage — sitting close to the cot at first and slowly increasing distance over several nights to help your baby feel secure while learning to settle independently.
The 12-month regression Often coincides with the transition from two naps to one. This shift in daytime sleep can temporarily throw nighttime sleep off balance. Your baby is also walking or getting very close to it — another significant developmental milestone that can disrupt sleep.
What helps: watch for readiness signs before dropping the second nap entirely. If your baby is resisting one nap consistently for two weeks or more, it's probably time to transition. Pushing through the transition decisively is often better than prolonging a two-nap schedule that's no longer working.
The 18-month regression Often the most surprising, because by this point many parents have relaxed into a settled sleep routine and the regression can feel like a step backwards into newborn territory. At 18 months, toddlers are navigating a surge in independence, language development, and big emotions — all of which can surface at bedtime.
What helps: firm, loving boundaries. At this age, consistency in your response to night waking is important. Toddlers this age are testing limits, and a predictable parental response — however many times it's needed — is more effective than varying your approach night to night.
General Principles for Surviving Any Sleep Regression
Protect the sleep environment A dark, cool, quiet room with white noise if helpful. The Stokke Sleepi's oval design and close-weave slats help maintain good airflow and a secure sleeping environment — details that matter more when sleep is already disrupted.
Prioritise the bedtime routine above all else When everything else feels chaotic, the routine is your anchor. Even a 15-20 minute consistent sequence of events before bed helps regulate your baby's nervous system and signals that sleep is coming.
Accept that it's temporary This is harder than it sounds at 3am, but it's true. Every sleep regression ends. The developmental leap that's causing it resolves, and sleep typically improves — often noticeably — on the other side.
Take care of yourself Tag-team with your partner if you can. Accept help when it's offered. Sleep deprivation is cumulative and real — your own rest matters too.
When to Speak to a Doctor
Most sleep regressions resolve on their own within a few weeks. If your baby is consistently sleeping very little, appears unwell, has a fever, or if you're concerned for any reason, always consult your paediatrician.
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