1: She's too young!

Babies that start sleeping through the night right away are legendary - and rare. For the first two months, newborns sleep on an irregular schedule, about 12 to 18 hours a day. An infant's sleep-wake cycle takes about six weeks to start to develop. In about three to six months, it should start to become regular. From three months to one year old, babies need a total of 14 to 15 hours of sleep (including naps). By about nine months old, 70% to 80% of infants will sleep through the night -- meaning five to six hours in a row.

2: You're his sleep aid

If parents rock a baby to sleep every night, he won't learn to fall asleep on his own.  He may cry to get what he needs - a parent's attention - in order to get back to sleep.  Put him to bed when he's sleepy, but not already asleep. He'll become a "self-soother" and learn to fall asleep on his own - even if he wakes up in the middle of the night.

3: He's over-tired

Toddlers and pre-school age children can be irritable without enough sleep - and that makes some distraught children resist sleep even more. Toddlers and preschoolers need 11 to 14 hours of sleep every 24 hours. Some of that time is spent napping. At this age, it's important to keep to regular bedtime, wake-up and nap times - as well as mealtimes and playtime.

4: Separation anxiety

Separation anxiety can add to sleep troubles. Talking, singing, rocking or extra feeds may turn this stage into a bad habit of night waking. At around six months old, you can encourage her to go back to sleep on her own. As long as baby doesn't appear sick, speak softly and rub her back, but don't pick her up or feed her. A nightlight may comfort toddlers who are afraid of the dark.

5: No regular bedtime routine

Doing the same things each night before bed helps your child recognise the change from being awake to being asleep. Create an age-appropriate, relaxing bedtime routine that includes events like a bath, story time, a light snack, then lights out. The routine should be the same each night and should always end in your child's room. Experts suggest you start a routine by the time your baby is four months old.

6: Awake at night

Whether it's separation anxiety, lack of routine, or just the desire to control their environment, some children resist bedtime or invent reasons to stay up later. They may ask for another story, drink, or a trip to the toilet. Go into your child's room and be strict but reassuring. Your visits should get shorter each time. Give them some choices about bedtime, such as the order of the bedtime activities, but not the time.

7: Not enough nap time

Believe it or not, if children don't get enough daytime sleep, they have trouble falling asleep at night. Most babies need two or three naps a day. Toddlers need at least one nap - young toddlers often take two. Most still take an afternoon nap until they're five. Tune in to your child's mood. If she's irritable and sleepy, let her nap, but don't let her nap close to bedtime - and don't miss naps.

8: Obstructive sleep apnoea

Sometimes children can't sleep due to obstructive sleep apnoea - when the airways are blocked, often by enlarged tonsils and nasal tissues called adenoids. Children with sleep apnoea usually snore loudly, have laboured breathing and restless sleep.  It affects about one in 100 children and is most common between three and seven, when tonsils and adenoids are at their biggest.  Treatment includes surgery or using a pressurised air mask (CPAP machine) at night.

Snoring

About 10% of children snore. They can snore for many reasons, including sleep apnoea, seasonal allergies, stuffiness from a cold or a deviated septum. If sleep isn't disturbed, your doctor probably won't treat snoring. See your GP if your child isn't sleeping well because of snoring or breathing problems. If snoring bothers sleep and it isn't an apnoea symptom, it may be treated with medicine, such as nasal steroid spray to shrink nasal tissues. 

10: Nightmares and night terrors

Bad dreams are usually harmless. They tend to end by the teenage years. If your child has a nightmare, he may be very scared and he can tell you about it. During night terrors, a child may act terrified, yet may still be asleep. But when he wakes, he won't remember it. Console your child during bad dreams.  Make sure he gets enough sleep and has a soothing bedtime routine. See your GP if bad dreams continue.

11: Sleepwalking

Children who have night terrors also often sleepwalk. When they're only partially awake they walk, talk, sit up in bed or do other activities. Their eyes may be open, but they're unaware. Most kids outgrow sleepwalking by their teens. Don't wake a sleepwalking child because you may scare her. Gently guide her back to bed. Keep the area around her safe: lock doors and put up safety gates near stairs.

12: Allergies, asthma and more

Some medical conditions can prevent kids from sleeping. Stuffy noses from allergies, colds and asthma can make it hard to breathe. In babies, colic, acid reflux, earaches or teething pain also can lead to poor sleep. Your GP may offer symptom relief to help your child sleep better.

13: Common medicines

Sometimes the medicine your child takes to treat a condition can affect his quality of sleep. Decongestants and antihistamines to treat colds or allergies can cause restless sleep. Side effects of ADHD medicines often include difficulty sleeping. If medicines are affecting your child's sleep, talk to your GP about changing the medicine, dose or timing.

14: The teen body clock

A teenager's sleep cycle changes during adolescence, making him more alert in the evening and sleepier in the morning. Work with your teen's new body clock, letting her do homework at night and sleep later if she can. However, sleep remains as vital to teens as when they were younger and they still need at least eight-and-a-half hours a night.  . Unfortunately, social pressures may conspire against teens getting the proper amount and quality of sleep.

Try a dummy or teddy bear

Sometimes having a familiar object close by can help a child drift off. A dummy can satisfy babies' need to suck and can encourage sleep, even in a child who is breastfeeding. Do try to wean your baby off by one year old. Special toys like security blankets or stuffed animals can offer comfort, too. White noise may drown out sounds that would otherwise wake up a baby or toddler.

Make a better room for sleep

A pleasant room can make it easier for your child to sleep. Make sure the room is dark (a small nightlight is fine) and the temperature is comfortable -- an adult in short sleeves should not be too hot or cold. Children may be comfortable in lightweight outfits such as one-piece sleepsuits. Keep the room quiet. Shut the door if your child can hear a TV or activity elsewhere in the house.

Know how much sleep is right

Is your child nodding off on her desk? Some children are so tired they fall asleep at school. Children aged between five and 10 years old need at least 10 hours of sleep a night. She should be able to fall asleep within half an hour of going to bed and should easily wake up at the time she needs to start her day. 

A no-screen-time bedroom routine

With constant access to phones, computers and video games, teens can be tempted to text, chat and play instead of sleep. Like all kids and adults, teens need a relaxing routine to wind down for bed. Interactive electronics that work the brain will keep your teenager awake and make him sleepy the next day. Keep TVs, computers and phones out of the bedroom and don't let your teenager stay up late with technology.

Children, stress and insomnia

There are many reasons children have trouble falling asleep or staying asleep. Although insomnia can have physical causes, children and teens may often blame stress. They may be thinking or worrying about homework, relationships or the next day's activities. Sleep medicine is rarely the answer. Help them relax with deep breathing and a calm bedtime routine. They should not use caffeine or electronics before bed, either. 

Related reading

• How much sleep do children need?
• Getting baby through the night
• Your newborn's sleep
• Baby skin care slideshow
• Toddler milestones slideshow
• Top surprises of life after baby arrives