Sleep patterns of New Zealand infants during the first 12 months of life.

The sleeping patterns of 874 infants aged 1-12 months were recorded by parents over a 6 day period. The most striking feature of the results was the wide range in total hours slept by infants of the same age, for example, the average total sleeping time per 24 h period for 4 month old infants was 14.8 h with a range of 11.0-19.3 h. Furthermore, over the 6 day period, individual infants showed wide variations in their sleeping times with a range as great as 12 h. Despite these wide variations, several clear trends emerged: from 1 to 8 months, a decrease with age of the average number of hours slept per 24 h period; and from 8 to 12 months, and a continuing shift towards a dominance of night over day sleep. The frequency of night wakings was, on average, 77%, a finding that contrasted sharply with parental perception of frequency of night waking; the transition from bassinet/carrycot to cot was most common between 3 and 4 months of age; 25% of babies slept with the light on, 9% used a dummy, and 37% sucked their fingers; first-born infants woke significantly less often at night than those with one or more sibling. These results provide an important comparative data set on the sleep patterns of infants.