Table 1 Baseline characteristics of participants in the Japan Environment and Children’s Study (2011–2014).
Non-Reassuring Foetal Status | No (n = 67,559) | Yes (n = 2,766) | ||
|---|---|---|---|---|
n* | % | n* | % | |
Maternal characteristics | ||||
Age at delivery (years) | ||||
<25 | 6,638 | 9.8 | 248 | 9.0 |
25–29 | 18,611 | 27.6 | 715 | 25.9 |
30–34 | 23,870 | 35.3 | 990 | 35.8 |
≥35 | 18,440 | 27.3 | 813 | 29.4 |
Educational background (years) | ||||
<10 | 3,042 | 4.6 | 114 | 4.2 |
10–12 | 21,053 | 31.6 | 780 | 28.5 |
13–16 | 41,680 | 62.5 | 1,803 | 65.8 |
≥17 | 959 | 1.4 | 42 | 1.5 |
Household income (million Japanese-yen/year) | ||||
<2 | 3,449 | 5.5 | 143 | 5.6 |
2 to <4 | 21,449 | 34.5 | 838 | 32.7 |
4 to <6 | 20,542 | 33.0 | 826 | 32.2 |
6 to <8 | 9,995 | 16.1 | 457 | 17.8 |
8 to <10 | 4,172 | 6.7 | 194 | 7.6 |
≥10 | 2,658 | 4.3 | 109 | 4.3 |
Smoking habits | ||||
Never smoked | 39,387 | 58.5 | 1,656 | 60.0 |
Ex-smokers who quit before pregnancy | 15,891 | 23.6 | 572 | 20.7 |
Smokers during early pregnancy | 12,033 | 17.9 | 531 | 19.3 |
Alcohol consumption | ||||
Never drank | 23,363 | 34.7 | 896 | 32.5 |
Ex-drinkers who quit before pregnancy | 12,508 | 18.6 | 454 | 16.5 |
Drinkers during early pregnancy | 31,509 | 46.8 | 1,410 | 51.1 |
Parity | ||||
0 | 28,677 | 42.6 | 2,081 | 75.4 |
≥1 | 38,680 | 57.4 | 678 | 24.6 |
Infertility treatment | ||||
No | 63,131 | 93.5 | 2,441 | 88.3 |
Yes | 4,405 | 6.5 | 324 | 11.7 |
Type of delivery | ||||
Vaginal | 56,584 | 83.8 | 1,340 | 48.5 |
Caesarean | 10,975 | 16.3 | 1,426 | 51.6 |
Gestational age (weeks) | ||||
37–38 | 22,478 | 33.3 | 640 | 23.1 |
39–40 | 38,691 | 57.3 | 1,621 | 58.6 |
41 | 6,390 | 9.5 | 505 | 18.3 |
Postpartum depressive symptoms at 1 month after delivery assessed by the Edinburgh Postnatal Depression Scale | ||||
No (score <8) | 57,076 | 85.8 | 2,251 | 82.4 |
Depressive (score ≥9) | 9,483 | 14.3 | 482 | 17.6 |
Infant characteristics | ||||
Birth weight | ||||
mean (standard deviation) (g) | 3,065 (364) | 2,978 (414) | ||
Small for gestational age | 4,702 | 7.0 | 469 | 17.0 |
Infant sex | ||||
Boys | 34,224 | 50.7 | 1,606 | 58.1 |
Girls | 33,335 | 49.3 | 1,160 | 41.9 |
