Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term

Alja Bijlsma, Victoria A.A. Beunders, Demi J. Dorrepaal, Koen F.M. Joosten, Inge A.L.P. van Beijsterveldt, Jeroen Dudink, Irwin K.M. Reiss, Anita C.S. Hokken-Koelega, Marijn J. Vermeulen

Research output: Contribution to journalArticleAcademicpeer-review


STUDY OBJECTIVES: Sleep impacts the quality of life and is associated with cardiometabolic and neurocognitive outcomes. Little is known about the sleep of preterm-born children at preschool age. We, therefore, studied sleep and 24-hour rhythms of preschool children born very preterm compared with full-term children.

METHODS: This was a prospective cohort study comparing sleep quality and quantity of children born very preterm (gestational age [GA] < 30 weeks) with full-term children at the (corrected) age of 3 years, using (1) 2 parent-reported questionnaires (Brief Infant Sleep Questionnaire and The Munich Chronotype Questionnaire) and (2) at least 3 days of triaxial wrist actigraphy combined with sleep diary. We performed regression analyses with adjustment for sex (corrected), age, and birth weight standard deviation (SD) score.

RESULTS: Ninety-seven very-preterm-born (median GA 27+5; interquartile range 26 + 3;29 + 0 weeks) and 92 full-term children (GA 39 + 3; 38 + 4;40 + 4 weeks) were included. Sleep problems and other reported sleep parameters were not different between groups. As measured with actigraphy, sleep and 24-hour rhythm were similar between groups, except for very-preterm born children waking up 21 minutes (4;38) minutes later than full-term children (adjusted P = .001).

CONCLUSIONS: Based on parent reports and actigraphy, very-preterm-born children sleep quite similar to full-term controls at the corrected age of 3 years. Reported sleep problems were not different between groups. Actigraphy data suggest that preterm-born children may wake up later than children born full term. Further studies are needed to explore how sleep relates to cardiometabolic and neurodevelopmental outcomes after preterm birth and whether early interventions are useful to optimize 24-hour rhythm and sleep.

CITATION: Bijlsma A, Beunders VAA, Dorrepaal DJ, et al. Sleep and 24-hour rhythm characteristics in preschool children born very preterm and full term. J Clin Sleep Med. 2023;19(4):685-693.

Original languageEnglish
Pages (from-to)685-693
Number of pages9
JournalJournal of clinical sleep medicine : JCSM : official publication of the American Academy of Sleep Medicine
Issue number4
Publication statusPublished - 20 Sept 2023


  • actigraphy
  • BOND study
  • circadian rhythm
  • inter-daily stability
  • intra-daily variability
  • PLUTO study
  • sleep problem
  • toddlers


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