New parents might be frustrated to realize that the sleep interruptions do not gradually end as their baby grows; external factors can cause regression in any baby’s sleep patterns. We reached out to some sleep and baby experts to find out what physical developments can affect a baby’s sleep quality. Keep reading to find out what they had to say.
Po-Chang Hsu

Po-Chang Hsu

Po-Chang Hsu MD, MS, Medical Content Expert at SleepingOcean.

Teething and Milestones

One of the most common physical developments that can disrupt sleep in babies is teething. During this life stage, babies have to deal with pain and discomfort, which can easily stand between them and restful slumber. In addition, babies sometimes experience low-grade fever that may also disrupt sleep.

Babies’ sleep may also get interrupted when they hit a new developmental milestone. Learning a new skill often encourages babies to try it out any time they get a chance, even in the middle of the night. For example, if the baby has started crawling, parents may often find their little one trying to crawl around the crib during the night. This occurrence is quite common, and parents simply need to wait for this stage to pass. Once the baby gets used to the new skill, they will get back to their regular sleep routine.

Sleep Regression and Teething

Two physical developments commonly impact baby sleep, and unfortunately, it’s not in a positive way.

Sleep Regression

The first is sleep regression. These are reasonably predictable stages when your child’s development, both mental and physical, triggers a change in their sleeping habits.

The first developmental step that causes regression occurs around eight weeks and results from the effects of melatonin provided to your child in utero wearing off and your baby’s little body needing to learn to produce enough melatonin to develop its circadian rhythm. Creating artificial darkness during daytime sleeps and ensuring playtime is in well-lit and bright environments can help to promote your baby’s natural production of melatonin.

The second occurs at around four months and can be quite dramatic for parents and children alike. During this time, your baby loses the ability to instinctively drift between sleep cycles and will fully awaken between cycles. If your child associates sleep with interactions with others, such as feeding or calming techniques like rocking, singing, or massage, this can create a real shock as your baby will still be unable to self settle and suddenly find themself awake with no one to help them sleep.

Given that sleep cycles are usually around the 45-minute mark, this can lead to some very challenging and sleepless nights for parents. It’s very helpful if you’ve already been teaching your baby to self-settle before this stage arrives, but if not, sleep routines can be a very effective way to teach your baby to self-settle. It will take one to three weeks to see results, but with military-like discipline and consistency in implementing your chosen routine, your baby will learn the cues that teach them to self-settle, sleep longer and soundly, and transition to sleep on their own.

Similar sleep regressions occur at around eight months, a little after their first birthday and around their second birthday. These are associated with the typical timing of major developmental stages, such as crawling and walking, and the significant degree of increased independence that two-year-olds are known for. This is also the underlying reason behind the “terrible twos.” Again, sleep routines are powerful tools for parents to keep their child’s sleep on track and make sure they are getting a good night’s sleep themselves!


The other major developmental stage that interrupts baby sleep is teething. The pain and discomfort will often result in sleepless and tearful nights and can be a very difficult period for families to navigate. Here, sleep routines will still help, but you are likely to need to address the physical problem, too.

Luckily there are many potential solutions available and it’s likely you will be able to find something that works for your little one:

  • Let them chew on a lightly frozen, clean, wet cloth.
  • Give them a teething toy to soothe themselves. There are many different types.
  • Give them a gum massage with your finger to soothe the pain. You can even add a bit of bonjela or other teething gel to improve the pain relief.
  • Let them eat a cold snack.
  • There are always children’s paracetamol or ibuprofen, too. When all else fails, these can be very effective at providing lasting relief to your baby through the night.
James Clarke

James Clarke

James Clarke is the founder of
Pierrette Mimi Poinsett

Pierrette Mimi Poinsett

Dr. Pierrette Mimi Poinsett, MD, Medical Consultant at Mom Loves Best.

Major Milestones Contribute to Regression

What is sleep regression? Sleep regressions are episodes when a baby is having more difficulty falling asleep after a period of falling asleep quickly. Other behaviors include skipping or taking shorter naps, waking up more frequently, fussing, and crying.

These regressions often occur as the baby achieves major developmental milestones such as rolling over, sitting up, crawling, talking, and walking. Sleep regressions most often happen at four months, eight months, 12 months, 18 months, and two years of age. Not all babies experience sleep regressions. Some may experience sleep regressions only once or twice.

What should you do if your baby is experiencing sleep regression? The critical thing is patience. Sleep regression may last from one to two weeks. Try an earlier bedtime if your baby is taking shorter naps or skipping naps. Your child may be transitioning from two daily naps to one daily nap. A baby may also experience frequent awakening during a growth spurt requiring larger or longer feeds.

Keep the bedroom dark and boring instead of turning on the light. This will convey the message that it is sleep time, not playtime. Above all, continue with a consistent routine of putting your baby down for sleep. Do not wait until the baby is entirely asleep before putting them down to sleep. This will help them learn how to self-soothe and fall asleep.

This is a crowdsourced article. Contributors are not necessarily affiliated with this website and their statements do not necessarily reflect the opinion of this website, other people, businesses, or other contributors.