With seven to twelve wakings per night, my daughter was far, far above the average for a baby of six months. There are differences across countries, but still. In a large survey encompassing 29,287 children aged 0 to 36 months, Jodi Mindell and her collaborators found that the subsample of 6-to-8-month-olds woke up on average 1.26 times per night in “predominantly Caucasian countries or regions” (Australia, Canada, New Zealand, United Kingdom, United States), and 2.12 times per night in “predominantly Asian countries or regions” (China, Hong Kong, India, Indonesia, Korea, Japan, Malaysia, Philippines, Singapore, Taiwan, Thailand, and Vietnam) (Mindell et al. 2010).
Another survey on 715 infants aged 6 to 12 months in the United Kingdom found similar results. The average number of night wakings was 2.06±1.72 per night in the subsample of 6-month-olds (120 infants), and 1.76±1.55 in the whole sample (715 infants) (Brown and Harries, 2015). In the whole sample, only 0.9% of infants woke up seven times or more each night. The authors also looked at the number of night feeds, which ranged from 1.80±1.79 at 6 months, to 0.60±0.97 at 12 months. Eighty percent of the whole sample had no more than two feeds per night.
The risk of being a poor sleeper was 2.6 times greater among the children who were fed and 1.7 times greater in children who were rocked to sleep or brought into the parents’ bed in response to an awakening, compared with children comforted in their beds
Evelyne Touchette, from Montreal Sacré-Coeur Hospital, and her collaborators, studied the factors statistically associated with fragmented sleep, in a representative sample of 1741 infants from the Canadian province of Québec. In this longitudinal study, the same children were followed at 5, 17 and 29 months of age. At 5 months, 23.5% of the infants slept less than 6 hours in a row (Touchette et al., 2005). At this age, factors like breastfeeding and cosleeping (broadly defined as not being alone in the bedroom) were significantly associated with fragmented sleep. However, two other factors were even more strongly associated, and those were parental behaviors after a nocturnal awakening: “The risk of being a poor sleeper was 2.6 times greater among the children who were fed and 1.7 times greater in children who were rocked to sleep or brought into the parents’ bed in response to an awakening, compared with children comforted in their beds” (Touchette et al., 2005).
This association with parental behaviors was even stronger at 17 months. At this age, 7.2% of infants slept less than 6 hours in a row, and the three factors most strongly associated with this were:
- Putting the child to bed already asleep or staying with him or her until asleep (risk of not sleeping 6 consecutive hours: 4.6 times greater than when the parents let the child fall asleep alone)
- Feeding the child after nocturnal awakenings (risk 3.8 times greater than when parents let him or her cry or comforting him or her in the bed)
- Rocking the child or bringing him or her into the parents’ beds after nocturnal awakenings (risk 2.3 times greater than when parents let him or her cry or comforting him or her in the bed).
Other researchers have even found correlations between the views on infant sleep of soon-to-be first-time mothers, before the child is born, and the quality of sleep infant sleep at 6 and 12 months. Liat Tikotzky and Avi Sadeh, from Tel Aviv University in Israël, asked 85 pregnant women about their views on infant sleep, using a questionnaire with hypothetical cases like the one below.
|Tom is a 9-month-old boy. When he wants something or feels uncomfortable he cries and screams loudly. He usually calms down quickly when he gets what he wanted. During the night, Tom wakes up many times and has difficulties falling asleep. (1=Strongly disagree, 2=Disagree, 3=Somewhat disagree, 4=Somewhat agree, 5=Agree, 6=Strongly agree)|
|It is better not to react each time Tom wakes up so that he can learn to calm down and fall asleep.||1||2||3||4||5||6|
|There are children who habitually wake up at night and it is hard to find a way to change this behavior.||1||2||3||4||5||6|
|One should go to Tom when he wakes up, so that he knows that there is always someone to soothe him.||1||2||3||4||5||6|
A few months later, after the infants were born, their sleep quality was measured both with actigraphy (a miniature wristwatch-like device attached to the infant’s ankle during the recording period) and through daily sleep diaries completed by parents. Infant sleep quality was measured at six and twelve months. The findings demonstrated that “maternal cognitions related to concerns about the infants’ distress at night were associated with more disturbed sleep, as reflected by a higher number of objective and subjective night wakings, while maternal cognitions emphasizing the importance of limiting parental involvement were associated with more consolidated sleep” (Tikotzky and Sadeh, 2009). Mothers who emphasized infants’ distress at night were more likely to actively help their infants fall back asleep, by nursing, feeding, or soothing the baby outside the crib or in parents’ bed (rather than using passive parental presence or brief soothing in the crib). Such an active involvement was in turn associated with a higher number of night wakings, like in the other studies mentioned above.
If cognitions shaped even before the infant is born can predict the quality of infant sleep, this suggests that infant temperament may not be the main cause of disturbed sleep. Modifying the parental response to night wakings could thus perhaps reduce the number of night wakings. Several research teams have experimentally tested this hypothesis, with various intervention types and on different age groups. In part 3 of this article, I present the studies where the mean age of infants was comprised between 6 and 12 months.
Mindell, J. A., Sadeh, A., Wiegand, B., How, T. H., & Goh, D. Y. (2010). Cross-cultural differences in infant and toddler sleep. Sleep medicine, 11(3), 274-280.
Brown, A., & Harries, V. (2015). Infant sleep and night feeding patterns during later infancy: Association with breastfeeding frequency, daytime complementary food intake, and infant weight. Breastfeeding Medicine, 10(5), 246-252.
Tikotzky, L., & Sadeh, A. (2009). Maternal sleep‐related cognitions and infant sleep: A longitudinal study from pregnancy through the 1st Year. Child development, 80(3), 860-874.
Touchette, É., Petit, D., Paquet, J., Boivin, M., Japel, C., Tremblay, R. E., & Montplaisir, J. Y. (2005). Factors associated with fragmented sleep at night across early childhood. Archives of pediatrics & adolescent medicine, 159(3), 242-249.