Table 1 Descriptive statistics of the study population (PREDO) and replication cohort (ITU)

Maternal characteristics

 Maternal age, years

32.5 (5.3)

34.9 (4.7)

 < 0.0001

 Education

 < 0.0001

  Primary or secondary education

204 (49.0%)

78 (16.3%)

  University degree

212 (51.0%)

400 (83.7%)

  Data not available

9 (2.1%)

11 (2.3%)

 Maternal BMI, kg/m²

27.0 (6.5)

23.7 (3.9)

 < 0.0001

 Gestational diabetes during pregnancy

  No gestational diabetes

335 (78.8%)

392 (80.2%)

0.62

  Gestational diabetes

90 (21.2%)

97 (19.8%)

 Hypertensive disorders during pregnancy

 < 0.0001

  Normotension

271 (63.8%)

461 (94.3%)

  Gestational hypertension

39 (9.2%)

7 (1.4%)

  Preeclampsia

43 (10.1%)

15 (3.1%)

  Chronic hypertension

72 (17.0%)

6 (1.2%)

 Gestational weight gain

0.07

  Inadequate

57 (22.5%)

117 (24.1%)

  Normal

77 (30.3%)

181 (37.2%)

  Excessive

119 (47.0%)

188 (38.7%)

  Data not available

172 (40.5%)

2 (0.4%)

Birth outcomes

 Child sex

0.52

  Boy

228 (53.7%)

252 (51.5%)

  Girl

197 (46.4%)

237 (48.5%)

 Delivery mode

0.99

  Vaginal delivery

324 (78.8%)

386 (78.0%)

  Caesarian section

87 (21.2%)

103 (21.1%)

  Data not available

14 (3.3%)

 Gestational age, weeks

39.5 (2.0)

40.0 (1.7)

 < 0.0001

  Term birth

394 (92.7%)

468 (95.7%)

0.06

  Preterm birth

31 (7.3%)

21 (4.3%)

 Birth weight, grams

3464.1 (610.6)

3505.6 (499.1)

0.05

 Admission to neonatal intensive care unit

0.003

  No

346 (83.0%)

439 (89.8%)

  Yes

71 (17.0%)

50 (10.2%)

  Data not available

8 (1.9%)

Neurodevelopment

 Cognitive developmental delay (F80, F81, F83 or ≤  − 2 SD ASQ communication or problem-solving skills)a

36 (8.5%)

38 (7.8%)

0.70

 Motor developmental delay (F82 or ≤  − 2 SD ASQ fine or gross motor skills)a

26 (6.1%)

25 (5.1%)

0.51

 Social developmental delay (F84 or ≤  − 2 SD ASQ personal social skills)a

13 (3.1%)

17 (3.5%)

0.73

 Number of neurodevelopmental delay across the 3 broad areas

0.10

 No delay in any area

370 (88.5%)

424 (86.7%)

 Delay in any of the areas

29 (6.9%)

51 (10.4%)

 Delay in any 2 of the areas

15 (3.6%)

13 (2.7%)

 Delay in all three areas

4 (1.0%)

1 (0.2%)

 Mean age at neurodevelopmental delay assessment, years

9.9 (2.4)

4.7 (1.4)

 < 0.0001

 Bayley Scales of Infant and Toddler Development

  Receptive language development

39.3 (2.8)

  Data not available

140 (28.6%)

  Expressive language development

42.1 (3.7)

  Data not available

132 (27.0%)

  Fine motor development

50.8 (4.5)

  Data not available

135 (27.6%)

  Gross motor development

63.6 (2.6)

  Data not available

283 (57.9%)

  Cognitive development

76.6 (3.4)

  Data not available

104 (21.2%)

 Mean age at Bayley Scales assessment, years

3.0 (0.2)

  Data not available

98 (20.%)