Sleep problems among children are very common, and improve by the time they reach the age of two, according to a first-of-its-kind study which may help parents understand if their toddler's sleep patterns are normal or not.
The study, published in the journal Sleep Medicine, found that the time taken to fall asleep reduces to an average of 20 minutes by the age of 6 months, and by the time infants are two years old, they wake up only once during the night on average.
According to the researchers from the Finnish Institute for Health and Welfare (THL) in Finland, an infant's sleep becomes more stable and consistent during the first two years, and the total amount of time spent in slumber reduces to around 12 hours per day as daytime naps get shorter.
However, they said, there can be large individual variations in the quality of sleep of babies and toddlers.
The study, based on data from approximately 5,700 Finnish children, noted that around 40 per cent of the parents of eight-month-old infants believed they were concerned about their child's sleep.
"Up until now, we have not had any reference values for good infant sleep that are based on large data sets," said Juulia Paavonen, study co-author from THL.
"Now we know that the individual differences are very large, and that patterns relating to falling asleep, waking up, staying awake at night and sleeping rhythms often develop at different rates," Paavonen said.
Through the study, the scientists hoped to examine how large the individual differences in sleep among infants can be, while still falling within the boundaries of normal child development.
"Those children whose quality of sleep is clearly different from the average would probably benefit from situation assessment at, for example, the child welfare clinic. There are many tools available for reducing children's sleep problems," Paavonen said.
According to the researchers, it is still difficult to provide a general clinical recommendation on the total amount of sleep required for infants, although sufficient sleep is certainly important for their well-being.
They said, the amount of sleep required depends on many factors.
"It is important to look at the child's well-being as a whole," Paavonen said.
However, if it takes longer than 40 minutes for an 8-month-old child to fall asleep, it is best to discuss the matter in the child welfare clinic, the scientists noted.
They said the same applies if a 6-month-old child normally wakes at night three times or more, or if an 8-month-old stays awake at night for over 60 minutes.
The study noted that it is also best for parents to consult clinicians if a child about an year old is awake for more than 45 minutes at night, or an 18-month-old infant is awake over 30 minutes.
"If the parents are very concerned about their child or their own ability to cope, help should be sought even before these levels are reached," Paavonen said.