Why Won't My Baby Sleep Through the Night? 7 Reasons and What to Do

“Is your baby sleeping through yet?” It’s the question every parent gets asked, and when the answer is no, it can feel like you’re the only one struggling. You’re not. Night waking is incredibly common, and in many cases, it’s completely normal for your baby’s age and stage of development.

But “normal” doesn’t mean you have to just accept it if it’s making you ill or unsafe. Here are the most common reasons babies don’t sleep through the night, and what you can actually do about each one.

1. Sleep Associations

This is the most common reason babies over 4 months old continue to wake frequently at night. If your baby falls asleep while being fed, rocked, or held, they associate those conditions with falling asleep. When they naturally wake between sleep cycles (which all humans do, roughly every 1–2 hours), they can’t get back to sleep without those conditions being recreated. The fix is to gradually help your baby learn to fall asleep in their cot, with you present but without needing to be held or fed to sleep. This doesn’t mean leaving them to cry — there are gentle ways to do this.

2. The Routine Doesn’t Fit

This one catches a lot of parents off guard. If your baby’s nap schedule doesn’t match their biological sleep needs, it can cause all sorts of problems at night. Too much daytime sleep and they’re not tired enough at bedtime. Too little daytime sleep and they’re overtired, which paradoxically makes them wake more, not less. Awake windows (the time between sleeps) change as your baby grows, and what worked at 3 months won’t work at 6 months. But following wake windows alone can mess up your baby's circadian rhythm, which will make it harder for them to fall asleep and/or stay asleep for nap AND during the night.

3. Hunger

For very young babies (under about 6 months), genuine hunger is often a legitimate reason for night waking. Most babies need to feed once or twice during the night. But if your baby is over 7 months, established on solids, and gaining weight well, frequent night feeding is probably a sleep association rather than a nutritional need. It’s worth looking at whether your baby is getting enough calories during the day, and whether the night feeds are full feeds or comfort sucks. It can be a bit "chicken and egg" so you may need to cut down the night calories to allow the daytime calories to increase.

4. The Sleep Environment

Sometimes the simplest changes make the biggest difference. A room that’s too light (even a sliver of light from a gap in the curtains can be enough), too warm, too cold, or too noisy can all disrupt sleep. Invest in proper blackout blinds to ensure the room is dark enough that you can see the outlines but not the details of the furniture, check the room temperature is between 16–20°C, and consider using continuous white noise to mask household sounds.

5. Discomfort or Pain

Reflux, cow’s milk protein allergy, teething, ear infections, and eczema can all cause night waking. If your baby seems to be in pain (arching their back, pulling at their ears, excessive spit-up, or a rash), see your GP first. No amount of sleep training will help a baby who is uncomfortable. I specialise in working with babies who have reflux and allergies, and it’s an area where many sleep consultants lack experience.

6. Developmental Leaps and Sleep Regressions

Babies go through major developmental shifts at around 4 months, 8–10 months, 12 months, and 18 months. During these periods, sleep can temporarily get worse as their brain is busy processing new skills. The key is to offer support and comfort without introducing new habits that you’ll need to undo later.

7. Early Morning Waking

If your baby treats 5am as morning, that’s often a sign that the daytime routine needs adjusting, the room isn’t dark enough in the early hours, bedtime is too early, or their bodyclock needs resetting. Early waking is one of the trickiest sleep issues to fix on your own because the causes aren’t always obvious, but it’s something I help families with regularly.

You Don’t Have to Just Push Through

I know there’s a culture of “just ride it out” around baby sleep. And yes, some babies do eventually figure it out on their own. But if you’re months into broken sleep and it’s affecting your health, your mental wellbeing, or your ability to enjoy your baby, you deserve support.

A consultation with a sleep consultant isn’t about being told you’re doing it wrong. It’s about having someone experienced look at your specific situation and give you a realistic, personalised plan to make things better — with support while you implement it.

Call me on 07977 462 252 for a free chat, or book your free call here. No judgement, no pressure — just help.