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Table 4 Methodological quality of observational studies included in the meta-analysis

From: Association between maternal sleep duration and quality, and the risk of preterm birth: a systematic review and meta-analysis of observational studies

First author, (Ref), yearSelectionComparabilityOutcome
Cohort studyRepresentativeness of the exposed cohortSelection of the non-exposed cohortAscertainment of exposureDemonstration that outcome of interest was not present at start of studyComparability of cohorts on the basis of the design or analysisAssessment of outcomeWas follow-up long enough for outcomes to occurAdequacy of follow up of cohorts
Trivedi et al., [30] 2018
Li et al., [31] 2017
Ota et al., [35] 2017
Blair et al., [36] 2015
Guendelman et al., [12] 2013
Okun et al., [33] 2012☑☑
Reutrakul et al., [34] 2011
Okun et al., [14] 2011
Micheli et al., [13] 2011☑☑
First author, (Ref), yearSelectionComparabilityExposure
Case-control studyIs the case definition adequateRepresentativeness of the casesSelection of ControlsDefinition of ControlsComparability of cases and controls on the basis of the design or analysisAscertainment of exposureSame method of ascertainment for cases and controlsNon-Response rate
Kajeepeta et al., [32] 2014☑☑
  1. The risk of bias of all studies included in this meta-analysis was based on the Newcastle–Ottawa quality assessment scale
  2. The definition/explanation of each column of the Newcastle–Ottawa Scale is available at