I often hear about ‘sleep regressions’. I actually hate that term, because they are always associated with developmental progress! But it is true that developmental changes can play havoc with your child’s sleep. I’m a paediatric nurse with over 15 years experience so I know my developmental milestones like the back of my hand – but most parents wouldn’t link these milestones to sleep problems unless they were pointed out, so I’m going to lay out the most common ages when sleep can be tricky.

Here we go…

Developmental Milestones (that may affect sleep) by age:


  1. Unaware of night and day
  2. Knows no reality apart from mother
  3. Sleeps most of the time except for feeding
  4. Falls straight into REM sleep, very little deep sleep
  5. Will poo during the night requiring nappy changes
  6. Can only tolerate being awake for 1-2 hours max
  7. Stops crying when picked up

Implications for sleep: Important to regulate body clock by exposure to 12 hours of light and 12 hours of dark per day, and make day and night distinctly different. Also to try to settle babies where they will ultimately be sleeping, using sensory cues such as shushing, patting or placing a gentle warm hand on their tummy to help them sleep. Night feeds at this age keep babies safe and reduce the risk of SIDS.

3 months:

  1. Much more alert and responsive
  2. Infants crave social interaction
  3. Distractibility may become a problem
  4. More aware of toys
  5. Will probably not need changing during the night
  6. Sleep cycles will lengthen and deepen by about 4-6 months

Implications for sleep: Plenty of interaction and stimulation in the day is important. Random timing of naps is still common, and most babies will wake at least every 3-4 hours at night for feeds. If you haven’t already done this, begin a flexible bedtime routine, so that your little one begins to know what is coming next.

6 months:

  1. Able to sit
  2. May begin cutting teeth
  3. Able to roll front to back (5-6 months) and back to front (6-7 months)
  4. Lots of babbling and deliberate vocalisation
  5. Starting solids

Implications for sleep: Babies at 5-6 months often begin waking more frequently at night, as they are learning so many new things! Whenever we learn, our brain is working hard, and this often manifests itself with more frequent night waking so that babies get an extra burst of energy to fuel their growing brain. One of the most important features of human milk is that it is higher than any other mammalian milk in lactose. The reason for this is that we have the most complex brains and the primary source of fuel for the brain is sugar – and therefore lactose in milk is designed to grow our complex brain! Most babies of 6 months have begun to organise their naps into 3 distinct times – usually mid-morning, lunchtime, and mid-afternoon, with the majority of their sleep still at night. Night feeds are still normal, and less than 20% of 6-month-olds sleep 12 hours a night.

9 months:

  1. Able to move on the floor by crawling, wriggling, shuffling or sliding
  2. Pulls to standing
  3. Enjoys dropping and throwing objects
  4. Responds to own name
  5. Understands that things and people may exist even if they can’t see them
  6. Separation anxiety

Implications for sleep: Even if sleep has not been a problem up till now, it is likely that your 9-month-old baby (or anywhere from 7-10 months actually!) will have a blip in their sleep habits about now. Babies get worried that if you disappear you may not come back, so they often wake to ‘check’ you’re still there. Try playing peepo games, increasing the distance between you and your little one, or leaving the room and popping back past the door again as they gain confidence that you always come back. They are also learning to crawl and pull up, and like to practice this in their cot. They may also pull themselves up to standing when you lay them back down again. The trick here is to stay low. Lie down on the floor next to your little one’s cot if you have to, and pretend to be asleep. Children are born social and like to meet our eye level, so if you stay low, they may decide to lie down to be nearer to you. Crafty, but it works! Babies often drop their mid-afternoon nap about now, and this can mean some cranky afternoons. Try an earlier bedtime to compensate.

12 months:

  1. May begin walking or cruising
  2. Understands simple instructions – ‘come to Mummy’
  3. Likes to be in sight and hearing of familiar people
  4. Responds to familiar sounds and songs
  5. Eats a family diet

Implications for sleep: This is a massive age for your child! Speech sounds, walking, eating more solid food, teeth…. You name it! Sleep is often disrupted around now, and you may need to go back to basics. Do you have a peaceful, nurturing bedtime routine? Does your child eat a varied, rainbow diet? Do they get enough fresh air and exercise during the day? Make sure you include plenty of love and support for your child at this age, as it’s scary gaining some independence! Cuddle your child whenever they want to be held, and provide plenty of opportunities to explore. A night feed is common at this age still, and most 1-year-olds have 2 naps per day.

15 months:

  1. Walks alone
  2. Lots of speech sounds
  3. Communicates needs and wishes by pointing, shouting or vocalising
  4. Able to say 2-6 recognisable words in correct context
  5. Enjoys books
  6. Emotionally up and down
  7. Requires lots of reassurance from parents
  8. Affectionate to familiar people

Implications for sleep: This is a common time to drop the morning nap. If your child has become difficult to get to sleep for their lunchtime nap, consider shortening or eliminating the morning nap. Or try bringing the lunchtime nap forward and doing an earlier bedtime. Make sure your child has plenty of exercise, a balanced family diet and lots of love and comfort at this age. Many 15-month-olds still wake at night for a feed.

18 months:

  1. Interested in climbing
  2. Turns pages of books
  3. Plays independently
  4. Likes songs, music and dancing
  5. Much more aware of soiled nappy, may give notice of impending toilet needs!!

Implications for sleep: This is a common age for sleep problems! 18-month-olds are busy little people and have a lot to do and learn. It’s a hard age as they are often pre-verbal, but have so much they want to get out! These children will often have another wave of separation anxiety, fuelled by their increasing independence. As much as it is exciting to have more independence, it is also scary, and so it is a common time for children to become clingy and whingy. They want to be ‘grown up’ yet are scared to leave your side. They need lots of patience, gentle boundaries and choices at this age. Give your child lots of limited choices throughout the day, so that they do not feel the need to exercise their right to choose the only things they have ultimate control over – Food, Sleep and Toileting. If you give away choices throughout the day, they are less likely to make a fuss about food, sleep and toileting. Be consistent, patient, and supportive at this age – it’s a tricky stage for your child! Your child still needs a nap, and night waking is still common, especially if solids have been slow to get off the ground.

2 years:

  1. May climb out of cot
  2. Speech is getting more sophisticated
  3. Able to follow a series of commands
  4. Follows parent around the house
  5. Demands attention constantly
  6. Resentful of attention shown to other children – often siblings come along around this time
  7. May show signs of readiness for potty training, but still unreliable

Implications for sleep: This is another very common age for sleep disturbance. Children of 2 years are developing language and increased ability to learn. Their character often really begins to emerge about now, and they can start making their feelings and wishes known very forcefully! This includes sleep. It is not uncommon for there to be a bedtime battle because your child misses you during the day. They may wake up due to increased brain activity caused by the massive surge in vocabulary and learning. You may be tempted to drop the lunchtime nap around now if bedtime has become difficult, which for some children will be appropriate. Do not get rid of naps until your child gets less sleep in 24 hours with the nap than without it. This is also a common time to move your child from a cot to a bed – which causes its own set of excitements and challenges! Night waking is still common even at 2. If it’s not a feed, it might be a night terror, a wet bed, or a fear of monsters in the cupboard. Your child’s brain is working overtime, and sleep is often collateral damage!

I hope that helps you understand where your child is coming from! Sleep is always a symptom of something more global going on, so take heart, take a deep breath, and take a minute to get your expectations of sleep in line with your child’s developmental stage.

Good luck!

Lyndsey Hookway is a paediatric nurse, health visitor, IBCLC, holistic sleep coach, PhD researcher, international speaker and author of 3 books. Lyndsey is also the Co-founder and Clinical Director of the Holistic Sleep Coaching Program, co-founder of the Thought Rebellion, and founder of the Breastfeeding the Brave project. Check Lyndsey’s speaker bio and talk brochure, as well as book her to speak at your event by visiting this page. All Lyndsey’s books, digital guides, courses and webinars can be purchased here, and you can also sign up for her free monthly newsletter here.