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From the Journals

Nearly half of infants don’t sleep through the night at 1 year

Publish date: November 12, 2018

Andrew D. Bowser

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Jury still out on infant sleep importance

Multiple studies looking at whether sleep matters in infants and no clear consensus, the answer going forward may depend on the primary outcome evaluated, Jodi A. Mindell, PhD, and Melisa Moore, PhD

“The jury is still out,” Dr. Mindell and Dr. Moore wrote in an editorial discussing the present study, which like others before it have found no relationship or limited relationships between infant sleep and later development.

On the other hand, several studies have found that fragmented sleep is associated with negative outcomes with respect to development, the editorial authors said.

One reason for the lack of agreement between studies may be differences in measurement, as the studies to date have used a variety of different measures for both sleep and development, they said. Moreover, the age of infants varies across studies, as does their location, raising the possibility that cultural differences may account for the disparate results.

Beyond that, they added, there is no single primary sleep outcome that has been applied, with some studies looking at sleep duration, and others looking at sleep consolidation, longest stretch of sleep, or duration of night wakings.

What some of these studies may miss is that many other factors may influence development, including genetics, nutrition, parental education, and interaction between child and parent.

“Sleep may be a drop in the bucket for broad development but, instead, have a more significant impact on next-day functioning,” they said.

Thus, the editorialists propose that future studies evaluate function instead of development to assess the importance of infant sleep, as some studies to date have shown that sleep in infants is important for language learning and memory consolidation.

“Rather than investigate gross development, we propose that day-to-day functioning and skill development may be better indicators of the impact of sleep on development in early childhood,” they concluded.

Dr. Mindell, and Dr. Moore are with the Sleep Center, Children’s Hospital of Philadelphia. Their editorial appears in Pediatrics. Dr. Mindell reported she is a consultant for Johnson & Johnson Consumer. Dr. Moore reported no financial relationships relevant to the article.

FROM PEDIATRICS

Just over half of infants get 8 hours of uninterrupted sleep at 12 months of age, an analysis of findings from a longitudinal birth cohort study showed.

It also found that whether an infant sleeps through night has no significant associated with any variations in mental or psychomotor development.

However, the rate of breastfeeding was significantly higher among infants who did not sleep through the night, investigators said in their report on the analysis, published in Pediatrics.

Being informed about the normal development of the sleep-wake cycle could be reassuring for parents, according to the authors, who said that new mothers tend to be “greatly surprised” by the sleep disturbance and exhaustion they experience.

“Keeping in mind the wide variability in the age when an infant starts to sleep through the night, expectations for early sleep consolidation could be moderated,” said Marie-Hélène Pennestri, PhD, of the Department of Educational and Counselling Psychology at McGill University, Montreal, and her coauthors.

Dr. Pennestri and colleagues reported on 388 mother-infant dyads in a longitudinal birth cohort study called Maternal Adversity, Vulnerability, and Neurodevelopment (MAVAN). Pregnant mothers were recruited from obstetric clinics in Canada. When their infants reached the age of 6 and 12 months, the mothers responded to questionnaires about sleep habits.

At 6 months, 62.4% of infants attained at least 6 hours of uninterrupted sleep, mothers reported, while 43.0% had reached 8 hours, the mothers reported. By 12 months of age, 72.1% of the infants attained 6 hours, and 56.6% attained 8 hours.

There were no associations between sleeping through the night and concurrent mental or psychomotor development, as measured by the Bayley Scales of Infant Development II at both 6 or 12 months of age, with P values greater than 0.05, investigators reported.

A similar lack of association between uninterrupted sleep and development or maternal mood was seen in a follow-up measurement at 36 months of age.

Sleeping through the night was likewise not associated with maternal mood, assessed using a depression scale with items that reflected symptom frequency in the previous week. “This is noteworthy because maternal sleep deprivation is often invoked to support the introduction of early behavioral interventions,” investigators said in a discussion of the results.

By contrast, sleeping through the night was linked to lower rates of breastfeeding as reported by mothers on retrospective questionnaires administered at both 6 and 12 months. At 12 months of age, 22.1% of infants sleeping through the night were breastfed, compared to 47.1% of infants not sleeping through the night (P less than 0.0001), Dr. Pennestri and colleagues reported.

However, that breastfeeding observation needs to be further investigated, according to the authors.

“The results of our study do not allow for the drawing of any causality between not sleeping through the night and breastfeeding,” they wrote.

Dr. Pennestri and coauthors said they had no financial relationships or potential conflicts of interest to disclose relevant to their report. They reported funding from the Ludmer Center for Neuroinformatics and Mental Health, Canadian Institutes of Health Research, and several other research institutions.

SOURCE: Pennestri MH, et al. Pediatrics. 2018;142(6):e20174330.

Nearly half of infants don’t sleep through the night at 1 year

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