Is your formerly perfect sleeper suddenly waking up in the middle of the night or wailing every time you put her down at her regularly scheduled naptime? 

You may be facing a case of sleep regression. Here’s what sleep regression is, when it usually happens, how long you can expect sleep regression to last and what you can do to help everyone sleep well again. 

What is sleep regression?

Sleep regression is a period of time, usually about two to four weeks, when a baby who’s sleeping well suddenly has trouble settling down for sleep or wakes up fussing in the middle of the night. 

What causes sleep regression in babies and why does it happen? 

A number of factors can cause a baby discomfort or make her anxious or restless, leading to sleep regression, including:

How long does sleep regression last?

Baby sleep regressions usually last about two to four weeks — the time for your little one to get used to a new routine or milestone or to recover from an illness — although the exact duration depends on the cause and can vary from baby to baby.

In the meantime, stick to your routines and consider testing a sleep training method if necessary.

Signs of sleep regression

The signs of sleep regression can vary based on the cause of your baby’s sleep problems. Here are some signs your baby may be going through a sleep regression: 

When sleep regressions happen

Sleep regression can happen at any time, since it’s linked to unpredictable factors like disruptions in routines or an illness.

But there are a few periods when sleep regression is relatively foreseeable, due to growth spurts, teething or reaching new milestones:

  • 3 to 4 months: The dreaded 4-month sleep regression is often the hardest for parents simply because it's the first. There are several culprits behind baby sleep problems at this age: the pain caused by teething, hunger linked to growth spurts and the excitement of rolling over for the first time.
  • 6 months: Babies often go through another growth spurt at about 6 months old. By this age, however, little ones are capable of sleeping through the night and may wake simply for snuggles — which means it might be time to test a sleep training method.
  • 8 to 10 months: Many babies begin crawling when they’re around 9 months old (although some start sooner and others later) and begin standing at around 10 months. Separation anxiety is also common (and perfectly normal) around this age, which may cause your baby to wake up looking for reassurance from you during the night.
  • 12 months: Sometime between 9 to 12 months, babies start standing up. At around the 1-year mark, others take their first steps (although the average age is 14 months, with some babies starting earlier and others waiting until the 18-month mark). Reaching big milestones can cause temporary sleep problems.

Toddlers often go through sleep regressions at around 15 months, 18 months, 2 years and 3 years that may be caused by nightmares and night terrors, fear of the dark, toddler teething and separation anxiety.

Tips for managing sleep regressions in your baby

Fortunately, sleep regression is usually temporary. Follow these tips to manage sleep regression in your baby:

  • Get to know and watch out for your baby’s sleep cues (like rubbing her eyes, fussiness, yawning, looking away), so you can get her to bed before she’s overtired — which makes it harder for her to fall and stay asleep.
  • Stick to a consistent bedtime routine. Think dinner, bath, book, lullabies and a few comforting words.
  • Ensure your baby is getting enough sleep during the day, as overtired babies are more likely to have problems sleeping at night.
  • If your baby suddenly starts crying in the middle of the night, give her a few minutes to fuss before you respond; she may self-soothe back to sleep. If she doesn’t, enter the room to check that everything’s okay, pat her on the head or tummy, quietly say a reassuring word and leave. Try to avoid rocking, cuddling or feeding your baby, as this may encourage her to regularly wake for your attention. If she keeps crying, you may want to say a few comforting words from the door and leave her again, repeating as necessary at increasing intervals of time.
  • Consider trying (or retrying) sleep training if your baby is at least 4 to 6 months old. Give it at least two weeks to see if it’s working.
  • Give her extra attention during the day and especially before bedtime. If your baby seems stressed out by a life change or has separation anxiety, this can help her to feel more secure at night.

Can you prevent sleep regression?

Unfortunately for many bleary-eyed new parents out there who’ve struggled with a sleepless baby, there’s no way to prevent sleep regression. It’s a normal part of baby and toddlerhood.

In the meantime, following a bedtime routine and sleep schedule can help reduce the likelihood of sleep problems. Hang in there and know that this, too, shall pass.

When to call the doctor about sleep regression

While sleep regression will very likely end on its own given some time, never hesitate to call your doctor if you have concerns or questions about your baby’s sleep or the potential cause behind sleep problems (like persistent nightmares).

If you’ve consistently stuck with a sleep training method for at least two weeks and your baby’s sleep is still disturbed and you’re not sure why, consider calling your doctor to see if he or she has any insights or advice to help your baby sleep better.

If your baby isn’t sleeping because she’s sick, know the signs it’s time to call her pediatrician, most commonly including fever (101 Fahrenheit or higher if your baby is 6 months or older), bloody nasal discharge, swollen glands or an earache (babies may pull at their ears).

Sleep regression isn’t fun for anyone. Know that it’s normal and will very likely pass, given time. Stick to your normal bedtime and sleep routines, which little ones find reassuring, and your baby will hopefully be sleeping like a champ again soon.

Frequently Asked Questions

What ages do babies sleep regress?

Sleep regression often happens at 3 to 4 months, 6 months, 8 to 10 months, 12 months, 15 months, 18 months, 2 years and 3 years.

How do I know if my baby is having a sleep regression?

More frequent night waking, trouble falling asleep at bedtime, increased fussiness, and suddenly resisting naps can all be signs your baby is having a sleep regression.