Table 2 Characteristics of studies included in the meta-analysis
First Author, (Ref), Year, Country | Study Design | No. of Case/Study size | Source of patient recruitment | Sleep assessment | Pregnancy outcome categories | Exposure categories (period of exposure measurement) | Risk Estimates (95% CI) |
|---|---|---|---|---|---|---|---|
Sleep Duration | |||||||
Trivedi et al., [30] 2018, India | Cohort study | 180/1977 | At household level | Questionnaire | Preterm birth | Sleep hours per day (> 8 h versus ≤ 8 h) during antenatal period | 0.93 (0.91–0.94) |
Li et al., [31] 2017, China | Cohort study | 32/688 | At three hospitals | Questionnaire | Preterm birth | Average night’s sleep (< 7 h versus ≥ 7 h) 12–16 weeks 24–28 weeks 32–36 weeks | 0.58 (0.67–5.05) 1.56 (0.29–8.29) 4.67 (1.24–17.5) |
Kajeepeta et al., [32] 2014, Peruvian | Case-control study | 479/480 | At hospital level | Questionnaire | Hours of sleep per night 0–24 weeks (≤6 h, ≥9 h versus 7–8 h) | ||
Spontaneous Preterm Birth | ≤6 h ≥9 h | 1.53 (1.08–2.17) 1.50 (1.04–2.16) | |||||
Spontaneous Very Preterm < 32 weeks | ≤6 h ≥9 h | 1.25 (0.74–2.11) 1.48 (0.89–2.47) | |||||
Spontaneous Moderate Preterm 32–33 weeks | ≤6 h ≥9 h | 1.82 (0.98–3.37) 1.98 (1.08–3.65) | |||||
Spontaneous Late Preterm 34- < 37 weeks | ≤6 h ≥9 h | 1.64 (1.11–2.43) 1.10 (0.72–1.70) | |||||
Spontaneous Preterm Labor | ≤6 h ≥9 h | 1.51 (1.00–2.29) 1.50 (0.99–2.27) | |||||
Preterm Premature Rupture of Membrane | ≤6 h ≥9 h | 1.60 (1.06–2.40) 1.17 (0.74–1.83) | |||||
Guendelman et al., [12] 2013, USA | Cohort study | 344/698 | A cohort | Questionnaire | Preterm birth | Total sleep duration 12–24 weeks (< 7 h, > 8 h versus 7-8 h) < 7 h > 8 h | 1.09 (0.80–1.48) 0.88 (0.57–1.48) |
Okun et al., [33] 2012, USA | Cohort study | 26/217 | Self-referral, physician referral, advertising, and screening in obstetrical ultrasound suites | Questionnaire | Preterm birth | Total sleep duration (< 7 h versus ≥ 7 h) at 20 week at 30 week (> 9 h versus ≤ 9 h) at 20 week at 30 week | 0.86 (0.29–2.59) 0.97 (0.31–3.02) 1.19 (0.38–3.75) 0.88 (0.20–3.91) |
Reutrakul et al., [34] 2011, USA | Cohort study | 56/116 | In all population | Questionnaire | Preterm birth | Sleep duration per night (< 7 h versus ≥ 7 h) Second trimester | 4.3 (1.1–16.7) |
Micheli et al., [13] 2011, Greece | Cohort study | 131/1091 | The Mother-child Cohort | Questionnaire | Sleep duration 24–36 weeks (≤5 h, 6-7 h versus ≥ 8 h) | ||
All preterm | ≤5 h 6-7 h | 1.7 (1.1–2.8) 0.9 (0.6–1.4) | |||||
Medically Indicated Preterm | ≤5 h 6-7 h | 2.4 (1.0–6.4) 1.2 (0.5–2.7) | |||||
Spontaneous Preterm | ≤5 h 6-7 h | 1.6 (0.8–2.9) 0.9 (0.6–1.4) | |||||
Sleep Quality | |||||||
Li et al., [31] 2017, China | Cohort study | 32/688 | At three hospitals | Questionnaire | Preterm birth | (PSQI > 5 versus PSQI≦5) 12–16 weeks 24–28 weeks 32–36 weeks | 2.04 (0.65–6.43) 5.35 (2.10–13.63) 3.01 (1.26–7.19) |
Ota et al., [35] 2017, Japan | Cohort study | 23/122 | At hospital | Questionnaire | Preterm birth | (PSQI > 5 versus PSQI≦5) at 16 week | 3.4 (1.2–9.9) |
Blair et al., [36] 2015, USA | Cohort study | 12/138 | The Ohio State University Wexner Medical Center and the surrounding community of Columbus | Questionnaire | Preterm birth | (PSQI > 5 versus PSQI≦5) Mid-pregnancy | 4.11 (1.04–16.25) |
Reutrakul et al., [34] 2011, USA | Cohort study | 74/116 | In all population | Questionnaire | Preterm birth | (PSQI > 5 versus PSQI≦5) Second trimester | 1.2 (1.0–1.3) |
Okun et al., [14] 2011, USA | Cohort study | 15/166 | A large university medical center | Questionnaire | Preterm birth | (PSQI > 5 versus PSQI≦5) 14–16 weeks 30–32 weeks | 1.25 (1.04–1.50) 1.18 (0.98–1.42) |