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

BACKGROUND: To assess the association of sleep duration and quality with the risk of preterm birth. METHODS: Relevant studies were retrieved from the PubMed and Web of Science databases up to September 30, 2018. The reference lists of the retrieved articles were reviewed. Random effects models were applied to estimate summarized relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: Ten identified studies (nine cohort studies and one case-controlled study) examined the associations of sleep duration and quality with the risk of preterm birth. As compared with women with the longest sleep duration, the summary RR was 1.23 (95% CI = 1.01–1.50) for women with the shortest sleep duration, with moderate between-study heterogeneity (I(2) = 57.4%). Additionally, as compared with women with good sleep quality, the summary RR was 1.54 (95% CI = 1.18–2.01) for women with poor sleep quality (Pittsburgh Sleep Quality Index > 5), with high between-study heterogeneity (I(2) = 76.7%). Funnel plots as well as the Egger’s and Begg’s tests revealed no evidence of publication bias. CONCLUSIONS: This systematic review and meta-analysis revealed that short sleep duration and poor sleep quality may be associated with an increased risk of preterm birth. Further subgroup analyses are warranted to test the robustness of these findings as well as to identify potential sources of heterogeneity.