Table 1 Sample characteristics.

N

1224

949

790

Cumulative prenatal stress (mean (SD))

0.36 (0.28)

0.44 (0.35)

0.51 (0.28)

<0.001

Life events domain (mean (SD))

0.10 (0.09)

0.11 (0.09)

0.09 (0.09)

0.001

Contextual risk domain (mean (SD))

0.16 (0.18)

0.20 (0.20)

0.25 (0.14)

<0.001

Personal risk domain (mean (SD))

0.03 (0.07)

0.05 (0.09)

0.11 (0.12)

<0.001

Interpersonal risk domain (mean (SD))

0.07 (0.09)

0.09 (0.13)

0.05 (0.09)

<0.001

Child sex, boys (n (%))

611 (49.9)

453 (47.7)

388 (49.1)

0.599

Gestational age at birth, weeks (mean (SD))

40.2 (1.5)

40.1 (1.4)

39.6 (1.5)

<0.001

Gestational weight at birth, grams (mean (SD))

3557 (506)

3529 (507)

3495 (479)

0.026

Maternal age at birth, years (mean (SD))

32.2 (4.2)

32.0 (4.3)

29.7 (4.4)

<0.001

Maternal tobacco smoking during pregnancy (n (%))†

Never smoked during pregnancy

857 (70.0)

665 (70.1)

Never a smoker

481 (60.9)

Smoked until pregnancy was known

109 (8.9)

78 (8.2)

Former smoker

219 (27.7)

Continued smoking in pregnancy

159 (13.0)

146 (15.4)

Current smoker

90 (11.4)

Maternal alcohol consumption during pregnancy (n (%))†

Never drank during pregnancy

351 (28.7)

302 (31.8)

<1 Glass per week

>357 (>45.2)

Drank until pregnancy was known

170 (13.9)

136 (14.3)

1+ Glass per week

170 (21.6)

Continued drinking occasionally

551 (45.0)

381 (40.1)

1-2 Glasses per week

11 (1.4)

Continued drinking frequently (1+ glass/week for 2+ trimesters)‡

152 (12.4)

130 (13.7)

>3 Glasses per week

<5 (<0.6)