Table 5.
Association between sleep during pregnancy and neonatal sleep in the Japan Environment and Children’s Study (2011–2014).
| No. of participants | No. of outcome | Maternal age adjusted model | Multivariable modela | ||||||
|---|---|---|---|---|---|---|---|---|---|
| % | RR | 95% CI | RR | 95% CI | |||||
| Five or more awakenings during the night | |||||||||
| Sleep time (h) | |||||||||
| < 6 | 3,932 | 245 | 6.2 | 1.03 | 0.90 | 1.17 | 1.07 | 0.94 | 1.22 |
| 6–7 | 11,999 | 764 | 6.4 | 1.04 | 0.96 | 1.13 | 1.07 | 0.98 | 1.16 |
| 7–8 | 24,914 | 1,524 | 6.1 | Reference | Reference | ||||
| 8–9 | 22,802 | 1,442 | 6.3 | 1.04 | 0.97 | 1.11 | 1.00 | 0.93 | 1.07 |
| 9–10 | 11,320 | 801 | 7.1 | 1.17 | 1.08 | 1.27 | 1.10 | 1.01 | 1.20 |
| > 10 | 5,183 | 324 | 6.3 | 1.08 | 0.96 | 1.22 | 1.06 | 0.95 | 1.20 |
| Bedtime | |||||||||
| 21:00–24:00 | 58,817 | 3,788 | 6.4 | Reference | Reference | ||||
| 24:00–03:00 | 19,541 | 1,179 | 6.0 | 0.95 | 0.90 | 1.02 | 1.04 | 0.97 | 1.11 |
| Other | 1,792 | 133 | 7.4 | 1.19 | 1.01 | 1.41 | 1.19 | 1.00 | 1.41 |
| Depth of sleep | |||||||||
| Very light | 5,567 | 436 | 7.8 | 1.29 | 1.17 | 1.43 | 1.27 | 1.14 | 1.40 |
| Light | 33,580 | 2,224 | 6.6 | 1.09 | 1.03 | 1.15 | 1.07 | 1.01 | 1.14 |
| Normal | 31,909 | 1,929 | 6.1 | Reference | Reference | ||||
| Deep | 7,510 | 418 | 5.6 | 0.92 | 0.83 | 1.02 | 0.94 | 0.85 | 1.04 |
| Very deep | 1,450 | 84 | 5.8 | 0.98 | 0.79 | 1.21 | 1.00 | 0.81 | 1.24 |
| p for trend < 0.01b | p for trend < 0.01b | ||||||||
| Feeling when waking up in the morning | |||||||||
| Very bad | 1,240 | 112 | 9.0 | 1.52 | 1.27 | 1.81 | 1.53 | 1.28 | 1.84 |
| Bad | 16,514 | 1,131 | 6.9 | 1.12 | 1.05 | 1.19 | 1.12 | 1.05 | 1.20 |
| Normal | 49,715 | 3,073 | 6.2 | Reference | Reference | ||||
| Good | 11,085 | 689 | 6.2 | 1.00 | 0.92 | 1.08 | 1.01 | 0.93 | 1.09 |
| Very good | 1,422 | 81 | 5.7 | 0.92 | 0.74 | 1.14 | 0.95 | 0.76 | 1.17 |
| p for trend < 0.01b | p for trend < 0.01b | ||||||||
| Sleeping longer during the day than at night | |||||||||
| Sleep time (h) | |||||||||
| < 6 | 3,914 | 915 | 23.4 | 1.19 | 1.12 | 1.27 | 1.16 | 1.09 | 1.24 |
| 6–7 | 11,958 | 2,663 | 22.3 | 1.14 | 1.10 | 1.19 | 1.11 | 1.06 | 1.16 |
| 7–8 | 24,868 | 4,843 | 19.5 | Reference | Reference | ||||
| 8–9 | 22,738 | 4,147 | 18.2 | 0.94 | 0.90 | 0.97 | 0.97 | 0.94 | 1.01 |
| 9–10 | 11,288 | 1,898 | 16.8 | 0.86 | 0.82 | 0.90 | 0.92 | 0.88 | 0.97 |
| > 10 | 5,167 | 964 | 18.7 | 0.93 | 0.88 | 0.99 | 0.96 | 0.90 | 1.03 |
| Bedtime | |||||||||
| 21:00–24:00 | 58,673 | 10,533 | 18.0 | Reference | Reference | ||||
| 24:00–03:00 | 19,499 | 4,516 | 23.2 | 1.28 | 1.24 | 1.32 | 1.18 | 1.14 | 1.22 |
| Other | 1,783 | 381 | 21.4 | 1.17 | 1.07 | 1.29 | 1.15 | 1.05 | 1.26 |
| Depth of sleep | |||||||||
| Very light | 5,550 | 1,162 | 20.9 | 1.09 | 1.03 | 1.15 | 1.08 | 1.02 | 1.15 |
| Light | 33,500 | 6,397 | 19.1 | 0.99 | 0.96 | 1.02 | 1.00 | 0.97 | 1.03 |
| Normal | 31,812 | 6,139 | 19.3 | Reference | Reference | ||||
| Deep | 7,489 | 1,427 | 19.1 | 0.99 | 0.94 | 1.04 | 0.96 | 0.92 | 1.02 |
| Very deep | 1,448 | 286 | 19.8 | 1.02 | 0.91 | 1.13 | 0.99 | 0.89 | 1.10 |
| p for trend = 0.15b | p for trend = 0.02b | ||||||||
| Feeling when waking up in the morning | |||||||||
| Very bad | 1,237 | 300 | 24.1 | 1.24 | 1.12 | 1.37 | 1.21 | 1.09 | 1.34 |
| Bad | 16,468 | 3,329 | 20.1 | 1.05 | 1.02 | 1.09 | 1.04 | 1.00 | 1.07 |
| Normal | 49,582 | 9,472 | 19.0 | Reference | Reference | ||||
| Good | 11,056 | 2,094 | 18.9 | 1.00 | 0.95 | 1.04 | 0.99 | 0.95 | 1.03 |
| Very good | 1,416 | 258 | 18.1 | 0.95 | 0.84 | 1.06 | 0.93 | 0.83 | 1.05 |
| p for trend < 0.01b | p for trend < 0.01b | ||||||||
CI, confidence interval; RR, relative risk.
aAdjusted for maternal age at delivery, smoking habits, alcohol consumption, pre-pregnancy body mass index, gestational age at birth, parity, infertility treatment, infant sex, small for gestational age, type of delivery, and postpartum depressive symptoms.
bLinear trend in the association was tested by assignment of ordinal variables for the five categories.